Role of calpain-10 gene variants in familial type 2 diabetes in Caucasians

The calpain-10 gene (CAPN10) has been implicated in type 2 diabetes (T2DM) susceptibility by both linkage and association in a Hispanic population from Starr County Texas. Common intronic variants seem to alter CAPN10 mRNA levels and were associated with insulin resistance but not diabetes in Pima Indians. The role of these variants in Caucasian populations is less clear. We found some evidence for linkage of T2DM to chromosome 2q approximately 20 cM proximal to the NIDDM1/CAPN10 locus. To test the hypothesis that CAPN10 is a diabetes susceptibility locus in Caucasian families at high risk for T2DM, we examined the influence of the three previously implicated CAPN10 variants on both diabetes risk and measures of insulin sensitivity and glucose homeostasis. We genotyped approximately 700 members of 63 families for 3 variants (SNP-43, SNP-19, and SNP-63). We tested each variant separately and as haplotype combinations for altered transmission from parents to affected children (transmission disequilibrium test), and we tested for an effect of each variant individually on measures of glucose and insulin during a glucose tolerance test in nondiabetic family members. Finally, we looked for an effect of each variant on measures of insulin sensitivity (S(I)) and insulin secretion estimated by frequently sampled iv glucose tolerance test and Minimal Model analysis. We could not confirm an increase in risk for T2DM susceptibility for any variant or for any haplotype combination, although we found marginal evidence for an increased risk of the 111/221 haplotype combination (P = 0.036) after ascertainment correction. However, both SNP-19 and SNP-63 increased fasting and/or postchallenge insulin levels, consistent with reduced insulin sensitivity. Furthermore, SNP-19 had modest effects on insulin sensitivity measured by homeostatic model, and on postchallenge glucose. The reduction in insulin sensitivity was confirmed by analysis of the subset of individuals who underwent iv glucose tolerance tests, where SNP-19 significantly altered the insulin sensitivity index. CAPN10 cannot be considered a major diabetes susceptibility gene in our population and seems unlikely to explain the observed linkage findings. However, CAPN10 influences insulin sensitivity and glucose homeostasis in nondiabetic members of kindreds at high risk for T2DM.     

Haplotype combination of Calpain-10 gene polymorphism is associated with metabolic syndrome in type 2 diabetes

Patients with metabolic syndrome are at increased risk of developing cardiovascular disease. The combinations of the haplotype created by the alleles of three single nucleotide polymorphisms (SNPs): SNP-43, -19, and -63 of the Calpain-10 gene (CAPN10), have been reported to be associated with the risk of type 2 diabetes in many populations. The aim of this study was to examine the association of the CAPN10 polymorphism with metabolic syndrome in patients with type 2 diabetes in Korea. Overall, 382 patients with type 2 diabetes were enrolled in this study. All the subjects were genotyped according to CAPN10 SNP-43, -19, and -63. The restriction fragment length polymorphism method was used for the three SNPs. The baseline presence of components of metabolic syndrome was determined. Two hundred and sixty-five (69.4%) patients had metabolic syndrome. Patients with the 111/121 haplotype combination showed a higher risk of hypertension than the other haplotype combinations (odd ratio (OR)=2.334, P=0.010). Patients with the 111/121 haplotype combination had a significantly high risk of metabolic syndrome (OR=1.927, P=0.042). The results of this study suggest that a novel 111/121 haplotype combination created by the CAPN10 SNP-43, -19, and -63 increases the susceptibility to the metabolic syndrome in patients with type 2 diabetes.     

Relationship of calpain-10 genotype to phenotypic features of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with an increased risk of impaired glucose tolerance and type 2 diabetes. Recent evidence suggests that variation in the gene encoding the cysteine protease calpain-10 influences susceptibility to type 2 diabetes. The present study was undertaken to determine whether variation in this gene is associated with quantitative traits pertinent to the pathogenesis of PCOS and diabetes. We studied 212 women with PCOS (124 white of European ancestry, 57 African-American, 13 Hispanic, 13 Asian-American, and 5 Middle-Eastern). Each subject was genotyped for 3 DNA polymorphisms in the calpain-10 gene associated with type 2 diabetes (SNP-43, -19, and -63). The white and African-American subjects were examined for association of these polymorphisms with phenotypic features of PCOS and type 2 diabetes. There were not enough individuals in the other groups for similar genotype/phenotype analyses. Nineteen (9%) of the 212 women with PCOS were diabetic and were not included in the genotype/phenotype analyses. Twelve (63%) of these subjects were African-American. Phenotypic traits in nondiabetic white probands did not differ whether analyzed for each individual SNP (SNP-43, -19, -63) or haplotype combination. Nor was there association of SNP-43, -19, or -63 with any of the phenotypic features of type 2 diabetes or PCOS in nondiabetic African-Americans. However, nondiabetic African-Americans with the 112/121-haplotype combination had significantly higher insulin levels, in response to an oral glucose challenge, as reflected in the area under the insulin curve (257,021 +/- 95,384 vs. 136,240 +/- 11,468 pmol/min; P = 0.03), compared with those with other haplotypes. This finding was particularly notable because the 112/121 subjects were less obese. The difference between groups in area under the insulin response curve remained significant (P = 0.002 by analysis of covariance) after adjustment for body mass index. In addition to its association with insulin levels in African-Americans, the 112/121-haplotype combination was associated with an approximate 2-fold increase in risk of PCOS in both African-Americans and whites.     

Variation in the calpain-10 gene is associated with elevated triglyceride levels and reduced adipose tissue messenger ribonucleic acid expression in obese Swedish subjects

Our aim was to investigate the possible role of the type 2 diabetes susceptibility gene CAPN10 in obesity. A case control study consisting of 235 obese Swedish subjects [body mass index, 40 (35-45) kg/m(2)] and 235 controls matched for age and gender [body mass index, 22 (21-24) kg/m(2)], and a transmission disequilibrium test consisting of 116 parents-offspring trios, where the offspring was abdominally obese [waist, 100 (95-110) cm], were performed. CAPN10 mRNA expression was studied in adipose tissue biopsies from 33 of the obese subjects participating in the case control study. The CAPN10 single-nucleotide polymorphism (SNP)-43 was genotyped using PCR followed by NdeI digestion or by allelic discrimination. CAPN10 mRNA levels were quantified using real-time RT-PCR with Cyclophilin A as an internal standard. No significant associations between CAPN10 SNP-43 and obesity were seen, neither in the case control study nor in the transmission disequilibrium test, but obese subjects homozygous for the SNP-43 G allele had significantly elevated triglyceride levels compared with subjects carrying the A allele [1.7 (1.1-2.4) vs. 1.4 (1.0-2.0); P = 0.03]. The CAPN10 mRNA expression in sc fat was significantly reduced in subjects with the SNP-43 G/G genotype compared with carriers of SNP-43 G/A (G/G, 0.33 +/- 0.02, vs. G/A, 0.51 +/- 0.09; P = 0.048), and a similar trend was observed in visceral fat (G/G, 0.52 +/- 0.06, vs. G/A, 0.65 +/- 0.10; P = 0.22). Our data suggest that reduced CAPN10 expression may be a risk factor for features associated with the metabolic syndrome in obese subjects, although variation in the gene does not seem to contribute to the risk for developing obesity per se.     

CAPN10基因变异与中国北方汉族人群血脂水平的关联研究

目的探讨CAPN10基因变异与中国北方汉族人群血脂水平的关系。方法研究选择427例2型糖尿病合并高血压个体以及547例年龄、性别相匹配的正常对照。所有个体均为中国北方汉族人,均未服用调脂药物。应用多聚酶链式反应-限制性片段长度多态性的方法对CAPN10基因的SNP-44、43、19、63多态进行基因型鉴定。结果应用线性回归模型校正年龄、性别和体重指数的作用,比较不同基因型和双体型个体的血脂水平差异。在病例组中,甘油三酯（TG）水平在SNP-63 CC纯合子个体和T等位基因携带者中有边缘性差异（P=0.05）。在对照组中,SNP-19多态11纯合子个体的TG水平高于等位基因2的携带者,但未达到统计学显著性（P=0.06）,而SNP-63 T等位基因亦有增高对照个体的TG水平的倾向,但在加性、显性和隐性模型中均未达到统计学显著性（P值分别为0.07,0.07和0.06）。在病例组和对照组中6种常见双体型个体的血脂水平均无统计学差异。结论CAPN10基因多态可能不是我国北方汉族人群血脂异常的主要危险因素。     

Common polymorphisms of calpain-10 are associated with abdominal obesity in subjects at high risk of type 2 diabetes

Aims/hypothesis The mechanisms by which the calpain-10 gene (CAPN10) affects the risk of type 2 diabetes are unclear. Therefore, we investigated the effects of four polymorphisms in CAPN10 (single nucleotide polymorphism [SNP]-43, SNP-44, Insertion/Deletion [Indel]-19 and SNP-63) on insulin secretion, insulin action and abdominal fat distribution in offspring of patients with type 2 diabetes.Subjects and methods Insulin secretion was determined by an IVGTT, insulin action by the hyperinsulinaemic–euglycaemic clamp and abdominal fat distribution by computed tomography in 158 non-diabetic offspring (age 34.9±6.3 years [mean±SD], BMI 26.2±4.9 kg/m²) of type 2 diabetic patients.Results SNP-43 (p=0.009 over the three genotypes, adjusted for age, sex, BMI and family relationship) and haplotypes carrying the A allele of SNP-43 were associated with intra-abdominal fat area. The A allele of SNP-43 was associated with intra-abdominal fat area in men (p=0.014) but not in women. SNP-44, InDel-19 and SNP-63 were not associated with intra-abdominal fat area or insulin action. Furthermore, we demonstrated in a separate sample of middle-aged men (n=234) who had a history of type 2 diabetes in first-degree relatives that the A allele of SNP-43 was associated with a large waist circumference, and high insulin levels in an OGTT.Conclusions/interpretation SNP-43 of CAPN10 may contribute to the risk of diabetes by regulating abdominal obesity in subjects with high risk of type 2 diabetes.     

Comment: CAPN10 alleles are associated with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is characterized by chronic anovulation infertility, hyperandrogenemia, and frequently insulin resistance. This study investigated whether polymorphisms in the CAPN10 gene are related with PCOS etiology. The allelic frequencies and genotypes of CAPN10 polymorphisms UCSNP-44, 43, 19, and 63 were determined in 55 well characterized women with polycystic ovaries and 93 unrelated healthy controls using spectrofluorimetric analyses and real-time PCR. Our data indicate that CAPN10 UCSNP-44 allele is associated with PCOS in the Spanish population (P = 0.01). These results support a role of Calpain 10 gene in PCOS susceptibility in humans.     

Calpain-10 gene polymorphism is associated with reduced beta(3)-adrenoceptor function in human fat cells

Polymorphism in the calpain-10 gene is linked to type 2 diabetes, insulin resistance, and decreased thermogenesis. In view of the role of beta-adrenoceptors in thermogenesis we investigated the relationship between beta(1)-, beta(2)-, and beta(3)-adrenoceptor-stimulated lipolysis in abdominal sc fat cells and 3 different previously described single nucleotide polymorphisms (SNPs) in the calpain-10 gene (SNP-19, SNP-43, and SNP-63). The study sample comprised 240 healthy subjects. A strong association between lipolytic beta(3)-receptor function in adipocytes and the SNP-19, which is a deletion/insertion (1/2) was observed in overweight subjects (body mass index, >25 kg/m(2)), but not in lean ones. No association was found between any of the polymorphisms and lipolytic function of either beta(1)- or beta(2)-receptors. Carriers of 1/1 in SNP-19 had 30-fold decreased lipolytic sensitivity of beta(3)-adrenoceptors in comparison to 1/2 or 2/2 carriers (P = 0.0019, by ANOVA). This was found in both genders and was not influenced by SNP-43 or SNP-63 in the calpain-10 gene or by the Trp(64)Arg polymorphism in the beta(3)-adrenoceptor gene. In conclusion, a deletion/insertion polymorphism in the calpain-10 gene (SNP-19) is associated with reduced beta(3)-adrenoceptor function in obesity. This could be of importance for regulating thermogenesis in overweight subjects.     

Four polymorphisms of the CAPN 10 gene and their relationship to polycystic ovary syndrome susceptibility: a meta-analysis

Objective To investigate the association between CAPN 10 gene polymorphism and polycystic ovary syndrome (PCOS) susceptibility. Design  Meta‐analysis of published case–control studies of four single nucleotide polymorphisms (SNPs) in CAPN 10 and PCOS susceptibility. Patients Women with PCOS. Measurements Odds ratios (ORs) and 95% confidence intervals (CIs) for heterozygous, homozygous, dominant model, recessive model and allele. Results A total of 11 studies were involved in the meta‐analysis. UCSNP‐63 was significantly associated with PCOS, with homozygous carriers (TT vs CC: OR = 0·64; 95% CI: 0·45–0·90) and recessive model (TT vs CC and CT: OR = 0·64; 95% CI: 0·45–0·90) being protective factors. In addition, UCSNP‐19 was significantly associated with PCOS, with recessive model (ins/ins vs del/del and del/ins: OR = 0·72, 95% CI: 0·59–0·88) and insert allele (ins vs del: OR = 0·85, 95% CI: 0·76–0·96) being protective factors, while heterozygous carriers (del/ins vs del/del: OR = 1·56, 95% CI: 1·24–1·94) and deletion allele (del vs ins: OR = 1·18, 95% CI: 1·04–1·32) being risk factors. However, no significant associations were found between UCSNP‐44, ‐43 and PCOS. Moreover, the results of the Rotterdam criteria subgroup analysis were similar with that of overall analysis. Conclusions This is the first report on the association between CAPN 10 UCSNP‐63 and PCOS in genotype, with homozygous carriers and recessive model being protective factors. Additionally, insert allele and recessive model of UCSNP‐19 are protective factors, while deletion allele and heterozygous genotype are risk factors for PCOS development.     

Association of calpain-10 gene with microvascular function

AIMS/HYPOTHESIS: Genotype could influence vascular function. In some populations, Calpain 10 gene polymorphisms increase susceptibility to diabetes or insulin resistance. Alterations in microvascular function could contribute to insulin resistance. This study investigated whether polymorphisms in the Calpain-10 gene influence microvascular function. METHODS: Skin maximum microvascular hyperaemia to local heating on the dorsum of the foot (30 min at 43 degrees C) was measured by Laser Doppler Fluximetry in 37 healthy volunteers. All were normoglycaemic according to World Health Organisation criteria, normotensive and not on any medication.Four polymorphisms in the calpain-10 gene were typed: SNP-44, SNP-43, SNP-19, SNP-63. The SNP common to all the described high risk haplotypes is the G-allele at SNP-43. This intron 3 polymorphism appears to influence gene expression. Microvascular function was examined in relation to polymorphisms at this site alone as well as the effects of the known extended high risk haplotypes using the SNP's above. RESULTS: Maximum microvascular hyperaemia was increased in the 21 subjects with G/G genotypes at SNP-43 compared to the combined group of subjects ( G/ A genotype at SNP-43 ( n=12) + A/ A genotype at SNP-43 ( n=4)), and the minimum microvascular resistance was reduced 49.4 (39.6-94.2) vs 67.5 (39.1-107.3) mmHg/V, p=0.007). Haplotype analysis of the hyperaemic response revealed no significant differences between haplotypes. The two groups did not differ in terms of anthropometric measures, blood pressure, insulin resistance or glucose. CONCLUSIONS/INTERPRETATION: The polymorphism that confers susceptibility to Type II (non-insulin-dependent) diabetes mellitus in some populations is associated in United Kingdom Caucasians with enhanced microvascular function in the presence of normoglycaemia.     

Association of calpain-10 polymorphisms with type 2 diabetes in the Tunisian population

BACKGROUND: Genome-wide analyses of the genetic predisposition to type 2 diabetes mellitus (T2DM) in different isolates and populations have identified regions of interest called non insulin-dependent diabetes mellitus (NIDDM) 1, 2, 3 and 4. At the NIDDM1 locus (2q37.3), calpain-10 (CAPN10) encodes for a ubiquitously expressed protease implicated in the two fundamental pathophysiological aspects of T2DM. This is a report of the results of a study of the association of four CAPN10 polymorphisms with T2DM in the Tunisian population. PARTICIPANTS AND METHODS: A total of 222 T2DM patients with a diabetes duration of 10 years or more and 206 healthy controls were enrolled to analyze the frequency distribution of four CAPN10 polymorphisms (UCSNP-43, UCSNP-19, UCSNP-110 and UCSNP-63) using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in the Tunisian population. We also investigated the association of T2DM with different haplotypes and haplotype combinations. RESULTS: Only the A allele of UCSNP-43 showed an association with T2DM (odds ratio, OR=1.86). We also identified a novel combination of haplotypes (121/221) defined by three polymorphisms (UCNSP-43, -19 and -63) that is associated with an increased risk of T2DM (OR=2.38). CONCLUSION: In this study involving the Tunisian population, we identified genetic variants within CAPN10 that are linked with T2DM and a novel haplotype combination, 121/221, associated with an increased susceptibility to T2DM.     

Association of variants in the fat mass and obesity associated (FTO) gene with polycystic ovary syndrome

AIMS/HYPOTHESIS: Variants in the fat-mass and obesity-associated gene (FTO) influence susceptibility to type 2 diabetes via an effect on adiposity/obesity. Given the important role of obesity in the aetiology of both polycystic ovary syndrome (PCOS) and type 2 diabetes mellitus, our aim was to establish whether FTO variants are also implicated in PCOS susceptibility. METHODS: We performed a genetic association study of FTO variant rs9939609 using case-control analyses, conducted in 463 PCOS patients (geometric mean BMI 27.5 kg/m(2)) and 1,336 female controls (geometric mean BMI 25.3 kg/m(2)) of UK British/Irish origin. We also sought evidence for associations between FTO variation and circulating testosterone levels in 324 UK PCOS patients and 1,000 women from the Northern Finland Birth Cohort of 1966. Outcome measures included FTO rs9939609 genotype frequencies by participant group and androgen measures (testosterone, free androgen index) by genotype. RESULTS: There was a significant association between FTO genotype and PCOS status in the UK case-control analysis, which was attenuated by adjustment for BMI (Cochran-Armitage test, odds ratio [per minor allele copy] 1.30 [95% CI 1.12, 1.51], p = 7.2 x 10(-4) [unadjusted], p = 2.9 x 10(-3) [adjusted]). This association was most evident in obese PCOS patients (PCOS patients below median BMI vs UK controls, p = 0.11; above median BMI vs controls, p = 2.9 x 10(-4)). No relationship between FTO genotype and androgen levels was seen. CONCLUSIONS/INTERPRETATION: We provide the first evidence that variants that predispose to common obesity also result in altered susceptibility to PCOS, confirming the mechanistic link between these conditions. The predominant effect of FTO variants on PCOS susceptibility is probably mediated through adiposity.     

Homozygous combination of calpain 10 gene haplotypes is associated with type 2 diabetes mellitus in a Polish population

OBJECTIVE: The polymorphisms of two genes have recently been associated with complex forms of type 2 diabetes mellitus (T2DM): calpain 10 and peroxisome proliferator-activated receptor-gamma (PPARgamma). Calpain 10 is a member of a large family of intracellular proteases. It was shown in Mexican-Americans and other populations that variants of three single nucleotide polymorphisms (SNPs), -43, -19, and -63, of this ubiquitously expressed protein influence susceptibility to T2DM. However, substantial differences were shown between ethnic groups in at risk alleles and haplotypes as well as in their attributable risk. Thus, it is important to determine the role of calpain 10 in various populations. AIM: To examine the role of calpain 10 SNPs -43, -19, and -63 in genetic susceptibility to T2DM in a Polish population. METHODS: Overall, 377 individuals were examined: 229 T2DM patients and 148 control individuals. The groups were genotyped for calpain 10 SNP-43, SNP-19, and SNP-63. SNP-19 was examined by electrophoresis of the PCR product on agarose gel by size, while the restriction fragment length polymorphism (RFLP) method was used for the two other markers. Differences in allele, genotype, haplotype, and haplotype combination distribution between the groups were examined by chi(2) test. RESULTS: Distributions of alleles, genotypes, and haplotypes at three loci defined by examined SNPs were not significantly different between the groups. However, the homozygote combination of 121 haplotype was more prevalent in the T2DM group than in the controls (17.9% vs 10.1%, P=0.039). No difference was observed in the 112/121 haplotype distribution. This heterozygous haplotype combination was associated with increased risk of T2DM in several populations. CONCLUSION: The results of our study suggest the association of calpain 10 121/121 haplotype combination created by SNPs -43, -19, and -63 with T2DM in a Polish population. However, we were not able to confirm the previously described role of the heterozygous 112/121 haplotype combination in susceptibility to T2DM.     

Type 2 diabetes candidate gene <Emphasis Type="Italic">CAPN10:</Emphasis> First,but not last

CAPN10, which encodes the cysteine protease calpain 10, was the first type 2 diabetes mellitus (T2DM) susceptibility gene identified through a genome-wide scan followed by positional cloning. A haplotype combination comprising three intronic CAPN10 single-nucleotide polymorphisms (UCSNP-43, -19, and -63) was associated with increased risk of T2DM in the population in which linkage was first found. Follow-up studies have been published from a wide range of populations; some confirm the original finding, but some do not. The exact function of calpain 10 remains to be determined, but it has been implicated both in glucose transporter 4 translocation to the cell membrane, regulation of pancreatic insulin secretion, and pancreatic β-cell apoptosis. This article reviews the genetic evidence for the association between CAPN10 and T2DM. The latest understanding of the biologic function of calpain 10 is discussed, along with results from recent genome-wide association studies that have failed to put CAPN10 among the top signals.     

Variants within the calpain-10 gene and relationships with type 2 diabetes (T2DM) and T2DM-related traits among Tunisian Arabs

BackgroundCommon variations in the calpain 10 (CAPN10) gene variants UCSNP-43, UCSNP-19 and UCSNP-63, and the 112/121 diplotype, are associated with an increased risk of type 2 diabetes (T2DM) and T2DM-related traits.MethodsThe association of UCSNP-43, -19 and -63 CAPN10 SNPs with T2DM was assessed in 917 Tunisian T2DM patients and 748 ethnically matched non-diabetic controls. CAPN10 genotyping was done by PCR-RFLP.ResultsSignificant differences in UCSNP-19 MAF, but not UCSNP-43 or -63, and genotype distribution were seen between patients and controls. Heterogeneity in UCSNP-19, but not UCSNP-43 and -63, genotype distribution was noted according to geographical origin. Obesity was associated with UCSNP-19, while raised fasting glucose was associated with UCSNP-63, and increased HDL was associated with UCSNP-43. Enrichment of homozygous UCSNP-19 2/2 was seen in overweight and obese compared with lean patients; logistic-regression analyses demonstrated a positive association of the 2/2 genotype with overweight [P = 0.003; OR (95% CI) = 2.07 (1.28–3.33)] and obese [P = 0.021; OR (95% CI) = 1.83 (1.10–3.07)] patients. Of the six CAPN10 haplotypes identified, significant enrichment of only haplotype 111 was seen in T2DM patients [Pc = 0.034; OR (95% CI) = 1.22 (1.06–1.41)], while the frequency of all identified CAPN10 diplotypes, including the high-risk 112/121, was comparable between patients and controls.ConclusionWhile CAPN10 UCSNP-19 SNP and haplotype 111 contribute to the risk of T2DM in Tunisian subjects, no significant association between CAPN10 diplotypes and T2DM was demonstrated.     

Identification of a polycystic ovary syndrome susceptibility variant in fibrillin-3 and association with a metabolic phenotype

CONTEXT: Polycystic ovary syndrome (PCOS), the most common reproductive endocrine disorder of premenopausal women, is also associated with metabolic abnormalities including insulin resistance and an increased risk for diabetes mellitus. We previously mapped a PCOS susceptibility locus to chromosome 19p13.2 near the dinucleotide repeat marker D19S884. OBJECTIVE: Our objective is to localize the chromosome 19p13.2 PCOS susceptibility locus and determine its impact on metabolic features of PCOS. DESIGN: Resequencing and family-based association testing were used to examine the effect of sequence variation within 100 kb of D19S884 on the reproductive and metabolic phenotypes of PCOS. SETTING: The study was conducted in an academic medical center. SUBJECTS: Genetic analyses were performed on DNA obtained from1723 individuals in 412 families with 412 index cases and 43 affected sisters of predominantly European origin (>94%). Genotype-phenotype associations were assessed in 601 women with PCOS and 168 brothers of affected women. RESULTS: D19S884 allele 8 (A8) within intron 55 of the fibrillin-3 (FBN3) gene showed the strongest evidence for association with PCOS of 53 variants tested (P(corrected) = 0.0037). A8 was also associated with higher levels of fasting insulin and homeostasis model assessment for insulin resistance in women with PCOS and higher fasting levels of proinsulin and proinsulin/insulin ratio in brothers. CONCLUSIONS: These findings strongly suggest that A8 of D19S884 is the chromosome 19p13.2 PCOS susceptibility locus. The association of D19S884 with markers of insulin resistance and pancreatic beta-cell dysfunction suggests that the same variant contributes to the reproductive and metabolic abnormalities of PCOS in affected women and their brothers.     

Identification of a protective haplogenotype within CAPN10 gene influencing colorectal cancer susceptibility

BACKGROUND AND AIM: Colorectal cancer (CRC) is one of the most prevalent types of cancer affecting both men and women in developed countries. Clinical and molecular evidence suggests that there are multiple biochemical pathways involved in its susceptibility, pathogenesis and prognosis. Several studies have reported a significant association between the incidence of CRC and type 2 diabetes mellitus (T2DM). However, genes associated with both conditions are rare. METHOD: We have analyzed the CAPN10 gene, a T2DM locus, using UCSNP-43, -44, -19, and -63 markers, looking for differences between 371 CRC patients and 605 unrelated controls of Spanish origin. RESULTS: We found that UCSNP-44 allele C is swept out from cases (OR = 0.16, P = 0.005). Moreover, the frequency of 2111/2111 haplogenotype is also statistically lower than expected in CRC patients (P = 0.006). CONCLUSION: Taken together, our results indicate a recessive model for the effect of CAPN10 variant UCSNP-44 influencing the risk of CRC and suggest a novel genetic link between T2DM and colon carcinoma.     

Calpain 1 O基因多态性与中国人2型糖尿病遗传易感性的相关性研究

目的 了解Calpain 10基因对中国汉族人2型糖尿病遗传易感性的影响。方法 采用病例对照研究方法：以聚合酶链式反应－限制性内切酶长度多态性（PCR－RFLP）技术，对211例2型糖尿病患者及127例正常对照Calpain 10基因SNP43及SNP19多态性进行基因分型。结果 同对照组相比，SNP43的G等位基因频率在2型糖尿病人群中显著升高（91．9％ vs 85.8%,P=0.01)。但SNP19位点等位基因频率在上述两组中的频率分布无显著差异。此外，本研究还观察到在正常对照组中，SNP43GG基因型与体重指数和腰－臂围比值增加相关。结论 Calpain 10基因SNP43位点G等位基因可直接或与其他糖尿病基因相互作用决定汉族人2型糖尿病的遗传易感性。     

Specific CAPN10 gene haplotypes influence the clinical profile of polycystic ovary patients

Recently, several research groups have evaluated CAPN10 gene in polycystic ovarian syndrome (PCOS) patients and other phenotypes, including hirsutism or intermediate phenotypes of PCOS. Molecular genetic analysis of CAPN10 gene indicates that different alleles may play a role in PCOS susceptibility and could be associated with idiopathic hirsutism. However, these observations are not exempt from controversy, because independent studies cannot replicate these preliminary findings. We present a haplotype-phenotype correlation study of CAPN10 haplotypes in 148 women showing ecographically detected polycystic ovaries (PCO) combined with one or more of these clinical symptoms: amenorrhea or severe oligomenorrhea, hyperandrogenism, and anovulatory infertility, as well as 93 unrelated controls. We have reconstructed and analyzed 482 CAPN10 haplotypes in patients and controls. We detected the association of UCSNP-44 allele with PCO phenotype in the Spanish population (P = 0.02). In addition, we identified several CAPN10 alleles associated to phenotypic differences observed between PCO patients, such as the presence of hypercholesterolemia (haplotype 1121, P = 0.005), presence of hyperandrogenic features (P = 0.05), and familial cancer incidence (haplotype 1111, P = 0.0005). Our results confirm the association of UCSNP-44 allele with PCO phenotype in the Spanish population. Moreover, we have identified novel candidate risk alleles and genotypes, within CAPN10 gene, that could be associated with important phenotypic and prognosis differences observed in PCOS patients.     

Calpain 10 and genetics of type 2 diabetes

Positional cloning studies conducted on a region of chromosome 2q providing evidence for linkage to type 2 diabetes implicated genetic variation at the calpain-10 gene (CAPN10) in susceptibility to type 2 diabetes. The variants identified in these studies are located in introns, rather than in coding sequence. It was proposed that the cumulative effects of a combination of variants, rather than variation at a single site, increase the risk of type 2 diabetes. Confirmation of the hypothesis that non-coding sequence variation in CAPN10 affects susceptibility to type 2 diabetes has implications for how we search for susceptibility variants and interpret results of positional cloning studies for complex disorders, and suggests a new pathway in glucose homeostasis. We review the results of follow-up studies on the CAPN10 finding, and consider the issues inherent in conclusively establishing that particular genetic variation affects a complex phenotype.