Genetic Targets May Be a Promising Future for Osteoporosis

Abstract

The definition, diagnosis and treatment plans for osteoporosis and osteopenia are based on the assessment of BMD by DEXA. However, this method faces many limitations and challenges. The main difficulty is its ability to assess fracture risk. The threshold for evaluating osteoporosis or osteopenia is of high specificity but of low sensitivity. The majority of osteoporotic fractures occur in individuals whose BMD values are above the osteoporotic threshold. These limitations necessitated the search for alternative solutions of better quality, including radiological and genetic ways, and applications with more input risk factors used in fracture risk assessment like FRAX application. Genetic diagnosis of osteoporosis is a real scientific revolution. There are thousands of point mutations implicated in osteoporosis. The future hope is to find a genetic diagnostic method for osteoporosis. This is very necessary because the treatments currently used are to delay the progression of osteoporosis; therefore, an earlier intervention will be effective. In addition, it serves the future prospects for gene therapy for osteoporosis.

1. Introduction

As defined by the World Health Organization (WHO), osteoporosis is present when BMD is 2.5 SD or more below the average value for young healthy women (a T-score of <−2.5 SD). A second, higher threshold describes “low bone mass” or osteopenia as a T-score that lies between −1 and − 2.5 SD. Osteopenia is a precursor stage of osteoporosis. The difference between the patient’s BMD and mean BMD of young females aged in the range of 20–29 years (divided by the standard deviation (SD) of the reference population) yields the T-score; comparing the BMD of a particular age, sex and ethnicity-matched adult reference population is called the Z-score. Treatment plans are linked to specific T-score values [1]. The problem is found in classification, diagnosis, and treatment of osteoporosis [1, 2, 3, 4, 5]. Searches are underway for solutions. Among the research directions is the genetic search for solutions to the problems facing DEXA in particular in assessing the condition of the bone and the subsequent selection of the appropriate treatment plan [6, 7, 8, 9, 10, 11]. Among the genes selected for study are the COL1A2 gene and LRP5 gene. The COL1A2 gene is chosen because it expresses the collagen protein responsible for bone elasticity by 90% [1]. DEXA completely ignores bone elasticity, as it only measures bone mineral density, which represents only the strength of the bone, not its elasticity. In order to achieve perfect bone, a balance must be achieved between the strength and flexibility of the bone. This is one of the biggest evidences of the inadequacy of DEXA to assess osteoporosis [9]. The COL1A2rs72658152 (located at 7q21.3,G > A1981,OMIM:120160) is chosen specifically because it is inherited in a dominant manner [12, 13] and has proven pathogenicity for postmenopausal osteoporosis. There is no idea how widespread it is in most societies [14]. On the other hand, the LRP5gene is chosen for its relationship to the formation of cortical bone [15], which forms the majority of the femur bone [1], meaning that LRP5 is a very important protein in the pathway for bone formation and construction in the femur region [16, 17] (femur region is one of the DEXA measurement sites, and therefore, it is possible to compare the DEXA results with the genetic results). The LRP5rs121908669 (located at 11q13.2, G > C 511, OMIM: 603506) is chosen because it is inherited predominantly [17], and it has not been genotyped nor in any research worldwide. It is proven to be a form of osteopetrosis. There is no idea how widespread it is in most societies [14]. The spread of applications such as FRAX can be seen as an attempt to solve the problems facing DEXA [11].

2. Methods (LRP5rs121908669 and COL1A2rs72658152)

2.1 Basic methods

As a practical study, the number of participants in the study was 150 women before and after menopause. A DEXA image was taken for all participants. The participants were divided into three groups according to the current classification of the World Health Organization related to T-Score (normal, osteopenia, and osteoporosis). Normal BMD female participants formed as the control group. Cases of mild osteogenesis imperfecta were diagnosed by a specialist in arthritis and rheumatology according to Sillence standards. The participants were classified into two groups who had symptoms of mild osteogenesis or not. A questionnaire was collected from all the participants, which included information about age, height, weight, body mass index, age of onset of bone complaint, age of the beginning of the menstrual cycle, age of the end of the menstrual cycle, number of children, family history, type of work. Women suffering from hypertension, diabetes, osteomalacia, surgical menopause, and cancer were excluded. Blood samples were collected from the participants on EDTA tubes. PCR, RFLP, DNA sequencing were performed for all samples for two SNPs (LRP5rs121908669 and COL1A2rs72658152). The work was done in accordance with the ethics of scientific research at Tishreen University, Syria.

2.2 Statistical study

The participants were distributed according to the classification of the World Health Organization into three groups (normal, osteopenia, osteoporosis). The distribution of participants was according to the diagnosis of mild osteogenesis imperfecta into two groups (yes/no). The participants with mild osteogenesis imperfecta were distributed according to the groups (normal, osteopenia, osteoporosis) into three groups. For the genetic results, no COL1A2rs72658152 appeared in any participant, so an attempt was made to study the pathological association which it is caused by this SNP. The genotypes of the LRP5rs121908669 were distributed according to three groups (GG, CC, and GC).

Several statistical applications (binary logistic regression test, Related-Samples McNemar Change Test, chi-square test) were used to study the relationship between mild osteogenesis imperfecta and postmenopausal osteoporosis and osteopenia. Chi-square test was used to study the association between carrier of (mild osteogenesis imperfecta—postmenopausal osteoporosis, osteopenia) and clinical data (height, age of onset of bone complaint). Statistical applications (Related-Samples McNemar Change Test, chi-square Test, Odd Ratio test) were used to study the relationship of genotypes of LRP5rs121908669 with femur T-score and the relationship of genotypes of LRP5rs121908669 with lumbar T-score. Chi-square test, Odd Ratio test, and likelihood ratio test were used to study the relationship of genotypes of LRP5rs121908669 with clinical data (body mass index).

3. Results

3.1 Data values for the participants

All the data of the studied participants are presented in the Table 1. It was obtained by the personal question of the participants and by referring to their files in the hospital and by clinical and radiological diagnosis. It includes data about the age of onset of the bone complaint, the age of the onset and end of the menstrual cycle, the number of children, the family history of the bone complaint, the history of bone pain in the participants, measurements of height and weight, body mass index BMI (kg/m2), history of fractures, classification of cases according to T-score according to the World Health Organization. The number of cases of mild osteogenesis imperfecta was according to the evaluation of specialists. Serum calcium and phosphorus concentrations were normal for all selected participants (Figures 1–4).

Variable	Case
Total number	150
Age	60(40, 80)
Age of beginning of menstrual	14(11, 17)
Age of end of menstrual	50.5(46, 55)
Weight	69.5(40,99)
Height	165(150,180)
BMI	29.69(17.99, 41.4)
Hearing features(YES/NO)	31/119
Dental features(YES/NO)	68/82
Data on fractures(YES/NO)	85/65
History of family orthopedic complaint(YES/NO)	56/94
Clinical history of bone complaint(YES/NO)	139/11
L2-L4(lumbar) Z-score	(−4.1, 3.1)
L2-L4 (lumbar)T-score	(−5.6, 1.2)
Femur Z-score	(−1.9, 1.1)
Femur T-score	(−2.2, 1.1)
Normal(T-score ≥ 1)	74
Osteopenia (−2.5) < T-score < (−1)	48
Osteoporosis T-score ≤ (−2.5)	28
Total(normal, osteopenia, osteoporosis)	150
Normal, mild OI	58/99
Osteopenia, mild OI	27/99
Osteoporosis, mild OI	14 /99
Total, mild OI	99/150

Table 1.

Data of the participants in the study (the results of the clinical diagnosis, the results of the radiological diagnosis, the data of the total questionnaire).

Figure 1.

LRP5rs121908669, results of migration of PCR products digested with BfiI enzyme (RFLP technique) on agarose gel, DNA ruler 20 bp, genotype CC (259) bp, genotype GG (bp67, 192 bp), genotype GC (bp67, bp192, bp259).

Figure 2.

DNA sequencing results for the three genotypes, LRP5rs121908669. GG(GGGGT), CC(GGGCT), GC(GGG(G/C)T).

Figure 3.

Migration results of COL1A2rs72658152, COL1A2rs72658152, digested with FspBI enzyme (RFLP technique) on agarose gel, DNA ruler 20 bp, genotype GG (255) bp.

Figure 4.

COL1A2rs72658152, DNA sequence results, negative results, normal genotype is (CTGG) GG(255 bp).

3.2 Genetic findings

3.2.1 Results of RFLP and DNA sequencing tests for both LRP5rs121908669 and COL1A2rs72658152

3.2.2 The frequency of SNPs LRP5rs121908669 and COL1A2rs72658152

The results of the PCR-RFLP and DNA sequencing tests for each of the two mutations were as shown in Table 2:

%	Number	Genotyping
64.66	97	GG/ LRP5rs121908669
13.3	20	CC/ LRP5rs121908669
22	33	GC/ LRP5rs121908669
No positive case was recorded, COL11A2G661S

Table 2.

Frequency of genotypes of the two studied mutations.

LRP5rs121908669: This study is the first of its kind in Syria as a genetic study related to LRP5, and it is the first study of its kind in the world regarding the genotyping of LRP5rs121908669.

It was found that there were 52 (34.66%) mutant cases (CC, GC) and 98 (65.33%) normal cases (GG). The mutant cases were distributed to 20 (13.3%) homozygous genotype CC and 32 (21.33%) heterozygous genotype GC.

The mutated cases (CC, GC) were distributed among low BMD cases (osteopenia, osteoporosis) and the control group (normal BMD cases) to ((19.51%) (16) (36) (52.94%)), respectively.

The proportion and number of cases of the homozygous genotype CC included 20 (13.3%). It was distributed to 5 (25%) versus 15 (75%) in the group of cases of low bone mineral density (osteopenia and osteoporosis) and the control group (cases with normal bone mineral density), respectively.

The percentage and number of cases of heterozygous genotype GC 21.33 (32%) were included. It was distributed to 11 (34.37%) compared to 21 (65.62%) in the group of BMD cases (osteopenia and osteoporosis) and the control group, respectively.

The proportion and number of cases of the normal genotype included GG 98 (65.33%). It was distributed among 66 (67.34%) compared to 32 (32.65%) in the group of carriers of low bone mineral density (osteopenia and osteoporosis) and the control group, respectively.

The CC and GC genotypes are associated with cases with normal BMD values in higher percentages than cases with low BMD values. This does not agree with the idea of an association between LRP5rs121908669 and cases with high bone mineral density—regardless of genotype—as reported in a Belgian study by Liesbeth Van Wesenbeeck et al. 2002 [17]. But it reinforces the studies indicating the existence of ethnic differences in the expression of the mutations themselves [3] (Europe, Middle East).

The association of CC and GC genotypes with low BMD cannot be neglected in some cases, contrary to the results of the Belgian study by Liesbeth Van Wesenbeeck et al. [17]. These cases may be attributed to the presence of protective factors (genetic or environmental factors) against the expression of the mutant-fixing gene (association with high BMD) or the presence of an interaction between the genes. Thus, the difference in the genetic expression of the mutation genotypes may be reflected in their effect on bone mineral density [18].

Not all carriers of CC and GC genotypes with various BMD states show clinical symptoms of autosomal dominant osteopetrosis1 ADO1, even though it is a proven pathogenic mutation of an ADO1. This contradicts the study by Liesbeth Van Wesenbeeck et al., 2002 [17]. It has been reported that LRP5rs121908669 is associated with ADO1 which is sometimes associated with generalized bone pain and hearing loss but certainly not associated with fractures [15, 16, 17, 19]. These differences in gene expression at the BMD level may be explained by race-related factors or genetic or environmental factors affecting gene expression [15].

It is possible that the clinical features in these studied participants with bone mineral density above +1 for LRP5rs121908669 are related to HBM high bone mineral more than to ADO1, and more clinical genetic studies are needed for further understanding. High bone mineral mass (HBM) and ADOI are diseases from the osteoporosis group. The radiological features are strikingly similar but HBM patients clinically have no complaints and are completely asymptomatic [20, 21] while at least some ADOI patients present with severe pain [20, 22]. ADOI is the only type of osteopetrosis that is not associated with an increased fracture rate but HBM is associated with an increased fracture rate [17, 19, 20].

The prevalence of cases carrying GC and CC genotypes is 52 (34.66%). It is a big percentage. This contradicts studies indicating that it is a rare mutation [15].

COL1A2rs72658152: No positive result was recorded. Therefore, it was directed to study the relationship of mild OI with low bone mineral density after menopause. This conjugation has been shown to be due to the COL1A2rs72658152 mutation, according to the NCBI.

3.2.3 The relationship of genotypes of LRP5rs121908669 with lumbar bone mineral density

The results of Odd ratio test, chi-square test, and Related-Samples McNemar Change Test which were applied to study the relationship between the genotypes of LRP5rs121908669 and lumbar BMD are shown in Table 3.

Genotypes	N.	BMD	McNemar%	OR	CI	Chi-square	P
GG	1	Normal	51.5	1.4000	1.092–1.794	6.302	0.012
	2	Osteopenia	0	0.495	0.268–0.913	5.919	0.015
	3	Osteoporosis	0	0.813	0.263–2.516	0.130	0.719
CC	1	Normal	0	0.712	0.546–0.928	3.846	0.05
	2	Osteopenia	1	3.462	0.910–13.165	7.731	0.005
	3	Osteoporosis	26.5	0.846	0.202–3.540	0.204	0.651
GC	1	Normal	0	0.822	0.625–1.081	1.658	0.198
	2	Osteopenia	10.4	1.375	0.714–2.648	0.989	0.320
	3	Osteoporosis	3	1.551	0.362–6.655	0.363	0.547

Table 3.

Results of the statistical relationships that study the relationship between lumbar T-score values and genotypes of LRP5rs121908669.

Osteopenia increases and osteoporosis decreases in lumbar bone (L1-L4) in carriers of the CC genotype. The appearance of normal BMD increases and osteoporosis decreases in lumbar bone in carriers of the GG genotype. The appearance of low lumbar bone mineral density (osteopenia) increases among carriers of the GC genotype.

It is noted that the genotypes of LRP5rs121908669 have an effect on the bone mineral density in the lumbar region, but the question could be “does it have an effect as important as the effect of hormonal factors on the bone mineral density in the lumbar region?”

In order to answer this question, a comparative study must be made between the statistical results in Table 3 specially between the participants who carry the CC and GC genotypes and suffer from low bone mineral density in the lumbar region and the participants who carry the GG genotype and suffer from low of bone mineral density in the lumbar region. Genetic patterns have greater influence than hormonal factors, knowing that all participants are women per and after menopause. It is preferable to measure the estrogen hormone in the participants and compare its concentrations with the appearing of genotypes and study the effect on the bone mineral density in the lumbar region.

This study is the first of its kind in the world. There is only one Belgian study that revealed this mutation by chance and it has not studied afterward, but in that study it was associated with an increase in bone mineral density without specifying the genotype, and this is contrary to the results of this research.

3.2.4 The relationship of genotypes of LRP5rs121908669 with femoral bone mineral density

The results of the odd ratio test, chi-square test, and McNemar test are shown in Table 4. These applications were applied to study the relationship between the genotypes of LRP5rs121908669 and femoral bone mineral density.

Genotype	Groups	McNemar %	OR(Odds ratio)	CI(95% confidence interval)	Chi-square	P
GG	Normal	2.5	1.830	1.344–2.493	13.750	0.000
	Osteopenia	0	0.366	0.185–0.723	10.765	0.001
	Osteoporosis	0	0.732	0.346–1.547	0.689	0.407
CC	Normal	0	0.558	0.417–0.746	8.683	0.003
	Osteopenia	1	7.231	1.056–49.516	7.731	0.005
	Osteoporosis	28	1.282	0.426–3.856	0.204	0.651
GC	Normal	0	0.712	0.514–0.986	3.463	0.063
	Osteopenia	8.7	1.652	0.818–3.334	2.263	0.133
	Osteoporosis	57.5	1.297	0.535–3.149	0.344	0.557

Table 4.

Results of the statistical relationships that study the relationship between femur T-score values and genotypes of LRP5rs121908669.

The appearance of low femoral bone mineral density (osteopenia, osteoporosis) increases and normal femoral bone mineral density decreases in carriers of the CC genotype. The appearance of normal femoral bone mineral density increases and the appearance of low femoral bone mineral density (osteopenia) decreases in carriers of the GG genotype. The appearance of low lumbar bone mineral density (osteopenia, osteoporosis) increases among carriers of the GC genotype.

It is noted that the genotypes of the mutation have effects on the bone mineral density in the femoral region and with a stronger effect than their effect on the bone mineral density in the lumbar region.

It can be explained that the LRP5rs121908669 mutation is one of the mutations of the LRP5 gene that encodes the LRP5 protein which is a part of the WNT pathway. WNT pathway is one of the most important pathways involved in the formation of cortical bone [19]. The cortical bone makes up the majority of the femur bone. Thus, the emergence of the greater effect of the genotypes of LRP5rs121908669 can be explained in the femur than in the lumbar bone, since the lumbar bone is formed mostly from spongy bone [1]. For more clarification, each of the femur and the lumbar bone consists of cortical bone and cancellous bone, but the proportion of cortical bone predominates in the femur, and the proportion of cancellous bone predominates in the lumbar bone [1].

This study is the first of its kind in the world. There is only one Belgian study that revealed this mutation by chance and it was not studied afterward, but in that study it was associated with an increase in bone mineral density without specifying the genotype, and this is contrary to the results of this research. However, it seems that it will receive wide attention after it was added to the lists of genetic laboratory kits for one of the major American international companies to manufacture laboratory kits for genetic analysis in 2022.

3.2.5 Correlation of the genotypes of LRP5rs121908669 with body mass index BMI

According to the results of the odd ratio test, the logistic regression test, and the chi-square test which are presented in Table 5, the following results are obtained:

Genotypes	N.	BMI groups	B/ OR	CI / P	Exp(B)/ OR	Chi-square	P
GG	1	<18.5	.915	0.173–4.832	.915	0.011	0.917
	2	[18.5–24.9]	.179	0.68–.471	.179	19.675	0.000
	3	[25–29.9]	.707	0.452–1.107	.707	2.507	0.113
	4	[30–34.9]	5.491	.2.499–12.064	5.491	23.707	0.000
	5	≥35	16.472	2.145–126.510	16.472	14.013	0.000
CC	1	<18.5	−8.244	.118	.000	0.060	0.806
	2	[18.5–24.9]	−8.374	.064	.000	6.868	0.009
	3	[25–29.9]	−4.712	0.016	.009	0.307	0.579
	4	[30–34.9]	−3.280	.082	.038	1.952	0.162
	5	≥35	.154	.049–.484	.154	12.466	0.000
GC	1	<18.5	−2.271	.455	.103	0.104	0.748
	2	[18.5–24.9]	−2.802	.300	.061	8.808	0.003
	3	[25–29.9]	−1.288	.421	.276	1.883	0.170
	4	[30–34.9]	.650	.673	1.915	19.997	0.000
	5	≥35	.423	.127–1.411	.423	2.023	0.155

Table 5.

Results of the statistical relationships that study the relationship between BMI and genotypes of LRP5rs121908669.

The appearance of the genotype GG increases in women who are carriers of BMI (obese, over obesity) and decreases in women with normal BMI. In other words, the characteristics of the carriers of the GG genotype in terms of BMI may be (obese or over obesity) and they cannot have a normal BMI. The GG genotype is a predisposing factor for obesity and over obesity, and a protective factor against reaching normal BMI.

The appearance of the CC genotype decreases in women who are carriers of BMI (overweight, over obesity). In other words, carriers of the CC genotype cannot be with BMI (overweight or over obesity). The CC genotype is a protective factor against BMI (over obesity and overweight).

The appearance of the genotype GC decreases in women who are carriers of BMI (normal, obese). In other words, the characteristics of GC genotype carriers may be in terms of BMI (normal, obesity). The GC genotype is a protective factor against obesity and a protective factor against reaching BMI (normal weight). This relationship is being studied for the first time globally.

3.2.6 The relationship of mild osteogenesis imperfecta OI with low bone mineral density after menopause

According to chi-square test results, the appearance of mild OI can be associated with all cases of bone mineral density in the lumbar position (the appearance of this association decreases with normal bone mineral density and increases in the rest of the cases). The appearance of mild OI is associated with cases of low bone mineral density in the lumbar position or the femoral position.

According to Related-Samples McNemar Change Test results, there is an association between the appearance of mild OI and normal bone mineral density in the femoral position (an inverse relationship).

No participant showed the studied collagen mutation (COL1A2rs72658152). However, there is a study indicating that COL1A2rs72658152 mutation is present in women who are carriers of symptoms of mild OI and at the same time they have osteoporosis or osteopenia after menopause (low bone mineral density). This study was a solution to one of the drawbacks of Loretta’s study [12, 23], the number of participants is larger. In fact, there is an association between carriers of symptoms of mild osteogenesis imperfecta and postmenopausal osteoporosis. What led to thinking that osteoporosis after menopause is not a primary osteoporosis [24] due to the presence of genetic causes for it and because it is a consequence of genetic diseases, as mild OI [23]. Mild OI is a genetic disease whose symptoms are very mild, it does not have serious clinical manifestations, but after menopause the condition develops into postmenopausal osteoporosis. This summary is explained statistically according to Table 6 containing the results of statistical studies (McNemar Change Test, Odd Ratio test, chi-square test) which were applied to study the relationship between mild osteogenesis imperfecta and femoral and/or lumbar bone mineral density in all its forms (normal/osteoporosis/osteopenia) (Figure 4, Table 7).

Mild OI with		McNemar%	B/OR	P/CI	OR/Exp(B)	Chi-Square Values	P
Lumbar	Normal	0.1	0.414	0.252–0.678	0.414	17.575	0.000
	Osteopenia	0	1.941	1.233–3.056	1.941	8.053	0.005
	Osteoporosis	0	1.941	1.004–3.753	1.941	3.927	0.048
	Low BMD	2.7	1.941	1.443–2.612	1.941	17.575	0.000
Femur	Normal	32.8	0.923	0.694–1.227	0.923	0.317	0.573
	Osteopenia	0	1.100	0.674–1.795	1.100	0.144	0.705
	Osteoporosis	0	1.213	0.418–3.520	1.213	0.126	0.722
	Low BMD	0	1.124	0.752–1.680	1.124	0.317	0.573
Lumbar/femur	Low BMD	10.8	1.758	0.000	5.800	20.635	0.000

Table 6.

Results of related-samples McNemar change test, odd ratio tests, chi-square tests to evaluate the relationship of mild OI to bones statues (normal, osteopenia, osteoporosis).

		B	P/CI	Exp(B)	Chi-square	P
Carriers of (Mild OI, low BMD)	[40–59] weight	2.868	.030	17.597	1.645	0.200
	[60–79] weight	.934	.317	2.544	0.724	0.395
	[80–99] weight	1.686	.092	5.397	9.865	0.352
	[150–159] height	.069	.951	1.071	1.165	0.280
	[160–169] height	.239	.816	1.270	0.467	0.494
	[170–179] height	4.138	1.018–16.817	4.138	5.193	0.023
	18.5 ≥ BMI	−2.590	.204	.075	0.358	0.550
	[18.5–24.9] BMI	−1.534	.294	.216	0.078	0.780
	≥35 BMI	1.505	0.333–6.793	1.505	0.290	0.590
	[40–50] age	.501	.712	1.650	1.477	0.224
	[50–60] age	1.668	.211	5.299	0.358	0.550
	[60–70] age	2.839	.033	17.107	6.253	0.012
	70–80 age	6.771	0.934–49.107	6.771	5.335	0.021
	[11] first of Menstrual	1.182	.229	3.262	2.955	0.086
	[12] first of Menstrual	−.457	.653	.633	2.713	0.100
	[13] first of Menstrual	.884	.349	2.419	2.212	0.137
	[14] first of Menstrual	.467	.614	1.595	0.016	0.898
	[15] first of Menstrual	2.257	0.702–7.259	2.257	2.093	0.148
	[40–42] end of Menstrual	.237	.763	1.268	0.329	0.566
	[43–45] end of Menstrual	.677	.391	1.967	0.401	0.527
	[46–48] end of Menstrual	−.040	.956	.961	1.961	0.161
	[49–51] end of Menstrual	−1.103	.144	.332	2.035	0.154

Table 7.

Results of the statistical relationships that study the relationship between carriers of {mild OI with low bone mineral density in the lumbar or femoral position (osteoporosis or osteopenia) after menopause} with the data of the participants.

3.2.7 The relationship of carriers (mild OI with low bone mineral density in the lumbar or femoral position (osteoporosis or osteopenia) after menopause with the data of the participants)

According to chi-square test results, this comorbidity (mild OI, low BMD) increases in tall women 170–179, and women who show a peak in bone pain complaints at the age of 60–80.

According to Related-Samples McNemar Change Test results, the emergence of bone pain complaints at the age of 60–70 is considered a risk factor for the emergence of this comorbidity.

3.2.8 Results of genetic test (LRP5rs121908669, COL1A2rs72658152) and FRAX vs. DEXA results (1: 0) as a case report

By comparing the genetic results of the two studied SNPs and the results of the application of FRAX and the results of DEXA for two clinical cases, there was agreement between the results of FRAX and the genetic results without their compatibility with the results of DEXA. The first case is 75 years old. Results of DEXA are osteopenia in the femur bone and normal in the lumbar bone. Results of FRAX are major osteoporotic 20, hip fracture 9.7. Therapeutic intervention is decided by the doctor. The genotype of LRP5rs121908669 is GC. There is not COL1A2rs72658152.

The second case is 45 years old. Results of DEXA are osteoporosis in the femur and lumbar bones. Results of FRAX are major osteoporotic 0.4, hip fracture 0. Therapeutic intervention is not needed as the doctor’s opinion. The genotype of LRP5rs121908669 is GG. There is not COL1A2rs72658152.

The results of DEXA conflict with the opinion of the specialist, while the results of FRAX agree with the opinion of the specialist. Genotypes of LRP5rs121908669 agree with the FRAX results, but vary with DEXA radiographic findings. FRAX is not a diagnosis tool. FRAX is for predicting fractures. But logically, it can be used in the validity of the current diagnosis, especially with the existence of the problem of the approved criteria (DEXA).

When a case is diagnosed as osteoporosis and requires therapeutic intervention according to the approved criteria, then FRAX is applied and the results are not predictive of fractures. Illogical something has been facing (case2). Or, when the case is not diagnosed as osteoporosis FRAX is applied and the results are predictive of fractures. In fact, this case requires therapeutic intervention, although it does not conform to the standards of the World Health Organization (case1). This requires more studies for comparing the results of FRAX with the results of DEXA on a larger scale of samples. This comparison is the first of its kind in the world.

4. Conclusion

• The results of the FRAX application show consistency with the results of the LRP5rs121908669 genetic diagnosis and the diagnosis based on the opinion of the clinician more than the compatibility of the results of DEXA with the genetic and clinical diagnosis. The World Health Organization has been contacted in this regard. Syrian Tishreen University is the first discoverer of this idea. This also strengthens the link between Tishreen University research and community services. This is a research service on a global and local level. It can be suggested to add the genetic factor especially LRP5rs121908669 to the application of FRAX. Syrian Tishreen University is proposed this idea for the first time in the world to prof. John Kanis.

• The association between mild osteogenesis imperfecta and postmenopausal osteoporosis is significant statistically. But there seems to be another reason for this association than COL1A2rs72658152. Postmenopausal osteoporosis is not primary osteoporosis. The World Health Organization has been contacted in this regard, and Syrian Tishreen University is the first discoverer of this idea.

• -The genotyping of LRP5rs121908669 is the first worldwide genotyping. Statistical studies showed the relationship of mutant genotypes (GC, CC) to osteopenia and osteoporosis in the lumbar region and the femur region, and the relationship of the normal genotype (GG) to normal bone mineral density in the lumbar region and the femur region. This is a world class search service. Syrian Tishreen University is the first discoverer of this idea.

• Cases of low bone mineral density in the femur region before the lumbar region in some postmenopausal women can be explained by the presence of the CC or GC mutant types of LRP5rs121908669 because of their clear effect on cortical bone (the relationship of LRP5 and cortical bone). This is a logical explanation for a realistic problem that was not previously explained, and question marks are always placed on it. This is a research service on a global and local level. Syrian Tishreen University is the first discoverer of this idea.

• It is obvious that cases of low of bone mineral density in the lumbar region are due to hormonal reasons (the relationship of spongy bone and hormonal factors), but it was found that there is a relationship to the genetic factor as well. This is a world class search service.

• The existence of specific morphological characteristics of the carriers of the LRP5rs121908669genotypes, and this reinforces the idea of morphological genetics to assist in the final clinical diagnosis. This is a world class search service. Syrian Tishreen University is the first discoverer of this idea.

• The current treatment plan should be based on drugs that reduce bone resorption or increase bone formation, according to the effect of the genetic variation and according to the signaling pathway to which it belongs. In addition to the idea of developing a targeted gene therapy for osteoporosis. It can be included in future prospects for the treatment of osteoporosis.

Acknowledgments

We express gratitude to our Research Team, Faculty of Pharmacy of Tishreen University and Atomic Energy Commission of SYRIA (AECS) for their support. Big thanks to Prof. Jean-Yves Reginster and Prof. Didier Hans and Prof. Stephen Dolye and Prof. Emmanuel Maheu for their support. Big Thanks for Prof. Nizar Mirali, Prof. Walid Al-achkar, Prof. Abd Alrazak Hassan and Prof. Haissam Yazigi. Big thanks to Sir. Ayman albloj, Ms. Sarah Reslan. Big thanks to Mss. Maison younes. Big thanks to Pharmacist. Mohammed Kbeili to help with statistical analysis. Huge thanks to the presidency of Tishreen University and the National Union of Syrian Students, Tishreen University, for the great support provided to me.

Conflict of interests

Eiman shahrour declares that they have no conflict of interest.

Funding

This research received no external funding.

Declaration

I confirm that this work is a part of an approved PhD thesis which was approved by university board’s decision No.1698 of 05/02/2019, and this work is an original and has not been published elsewhere, nor is it currently under consideration for publication elsewhere.

Ethical approval statement

The work was approved by the Ethics Committee in Syrian Ministry of Higher Education and written informed consent was obtained from all the participants according to the Declaration of Helsinki. The ethical approval for this clinical case study has the number N.1698 of 05/02/2019.

Informed consent statement

“Informed consent” was obtained from all subjects involved in the study. Written informed consent has been obtained from the patient(s) to publish this paper.

Data availability statement

The data that support the findings of this study are available from the corresponding author (Eiman M. Shahrour), upon reasonable request. All relevant material is included in this publication.

Supplemental material

Supplemental material referenced in this chapter can be downloaded at: https://bit.ly/3l1KEOV