Study on the mitochondrial DNA mutations in familial diabetes mellitus in Chinese population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the prevalence of mutations or variants of the mitochondrial DNA (mtDNA) in familial diabetes mellitus in Chinese population, and to explore the relationship between mtDNA mutations or variants and diabetes.</p><p><b>METHODS</b>Seven hundred and seventy randomly selected, unrelated probands of diabetes pedigrees and 309 controls over 60 years of age with normal glucose tolerance were recruited. PCR-RFLP and PCR-direct sequencing were applied to the screening of mtDNA mutations or variants, including the mutations at nucleotides 3243, 3256 in tRNALeu region, 12258 in tRNASer region, 14709 in tRNAGlu region, 8296, 8344, 8363 in tRNALys region, 3316, 3394, 3426 in ND1 region and 12026 in ND4 region.</p><p><b>RESULTS</b>In the diabetic group, 13 (1.69%) had mt3243 A>G mutation, 9(1.17%) had tRNAGlu 14709 T>C variant, 17 (2.21%) carried mt3316 G>A variant, 18 (2.34%) had mt3394 T>C variant, and 28 (3.63%) harbored the 12026 A>G variant. In the control group, the 14709, 3316, 3394, 12026 variants were detected in 5(1.62%), 5(1.62%), 6(1.94%), and 9(2.91%) subjects respectively. The 3256, 8296, 8344, 8363, 3426 and 12258 point mutations were not detected both in the diabetic patients and the controls. In the diabetic group, we found two double mutations, one was A3243G and T3394C, the other was A3243G and A12026G. Except that the A3243G mutation was only observed in the diabetic group, the frequencies of the other variants mentioned above were not statistically different between the diabetic and control groups. Moreover, clinical characteristics such as age of onset, BMI, and insulin resistance index were not different between diabetic patients with and without the variants.</p><p><b>CONCLUSION</b>The tRNA (LeuUUR) 3243 A>G mutation may be the major cause of diabetes, representing 1.69% of the familial diabetes mellitus in Chinese. The other variants may be polymorphisms in this population, and the mutations not detected in our studied population may not be common contributors to diabetes mellitus in Chinese.</p>

Prevalence and clinical characteristics of the mitochondrial tRNA(Leu(UUR)) gene 3243 A to G mutation in familial diabetes mellitus in Chinese population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the prevalence and clinical characteristics of the A to G mutation at nucleotide 3243 of the mitochondrial tRNA(Leu(UUR)) gene in familial diabetes in Shanghai, Jiangsu and Zhejiang Province of China.</p><p><b>METHODS</b>The mt3243 A to G mutation in 770 randomly selected, unrelated probands of diabetic pedigrees were screened by PCR-RFLP technique and PCR-direct sequencing. Genetic and clinical analyses were further performed in the probands and their family members.</p><p><b>RESULTS</b>Thirteen diabetic patients (13/770, 1.69%) with mt3243 A to G mutation were detected. Eleven diabetic patients and 8 normal glucose tolerance (NGT) first-degree relatives of these 13 probands were also found bearing the mutation. Seventeen patients were associated with sensory hearing loss. In the 24 patients harboring the mutation, the majority had lower body mass index (BMI), 18 showed typical maternal inheritance, 15 had sensory hearing loss, 13 had insulin resistance and 14 required insulin therapy due to secondary failure to oral hypoglycemic agents.</p><p><b>CONCLUSION</b>The mutation of mt3243 A to G in the mitochondrial tRNA(Leu(UUR)) gene is an important cause of diabetes in Shanghai, Jiangsu and Zhejiang Province of China. Mitochondrial gene mutation diabetes (MDM) is clinically characterized by early onset, emaciation, maternal inheritance, sensorineural hearing loss, and lower islet beta cell function, and some have insulin resistance.</p>

Relationship between SLC12A3 gene Arg913Gln polymorphism and type 2 diabetic nephropathy in Han population of Shanghai / 上海第二医科大学学报

Objective To explore the relationship between Arg913Gln(G→A) polymorphism of solute carrier family 12 member 3 (SLC12A3) gene and diabetic nephropathy (DN) in type 2 diabetes mellitus (T2DM) in Han population of Shanghai. Methods Two hundred and fifty-eight Han ethnic people in Shanghai with T2DM (T2DM group) were divided into non-DN group (DN0 group, n=95) and DN group (n=163) according to 24 h urine albumin excretion rate (AER), and those in DN group were subdivided into microalbuminuria group (DN1 group, n=95) and macroalbuminuria group (DN2 group, n=68). Besides, 82 people with normal results of oral glucose tolerance test (OGTT), without diabetes mellitus and nephropathy were served as controls. PCR-sequencing was used to detect the genotypes of Arg913Gln polymorphism of SLC12A3 gene. Genotypic and allelic frequencies and clinical characteristics were compared among groups. Results Three genotypes (GG, GA and AA) were detected. The frequencies of GA+AA genotype and A allele in T2DM group were higher than those in control group, while there was no significant difference between groups (P>0.05). There was no significant difference in genotypic or allelic frequencies among subgroups of T2DM group (P>0.05). The level of triglyeeride (TG), AER, level of fasting insulin (FINS) and HOMA-IR in patients with GA+AA genotype were significantly higher than those in patients with GG genotype in T2DM group (P<0.05). Conclusion Arg913Gln(G→A) polymorphism of SLC12A3 gene is not significantly associated with T2DM and DN in Han population of Shanghai. The AER of people with GA+AA genotype is significantly higher than that with GG genotype. Arg913Gln (G→A) polymorphism of SLC12A3 gene may predict the risk of increase of albuminuria in patients with T2DM in Han population of Shanghai.

The genetic and clinical characteristics of transcription factor 1 gene mutations in Chinese diabetes / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the genetic and clinical features of mutations and sequence variations of the transcription factor 1 gene (TCF1, HNF-1A) in Chinese with familial early-onset and/or multiplex diabetes mellitus.</p><p><b>METHODS</b>All ten exons of the TCF1 gene were screened, including exon and intron junctions, by direct sequencing method in 341 unrelated Chinese subjects, including 80 healthy controls and 261 probands of early-onset and/or multiplex diabetes pedigrees.</p><p><b>RESULTS</b>Five mutations were found in all. Four of the 5 different TCF1 mutations were newly identified novel mutations(T82M, Q130H, G253G, P353fsdelACGGGCCTGGAGC), mean body mass index of mutation carriers was 21.9 kg/m (2), and insulin secretion was impaired in the mutation carriers. In this study, the maturity-onset diabetes of the young type III (MODY3) only accounted for 3% of Chinese early-onset diabetes. Moreover, eleven substitutions were identified in 261 probands. Of them, three variants IVS1-8 (G-->A), IVS1 -128 (T-->G ) and IVS2+21 (G-->A) were not observed in 80 healthy controls and one of them IVS1-8 (G-->A) was not reported previously and the two promoter variants co-segregated with diabetes.</p><p><b>CONCLUSION</b>TCF1 gene is not a common cause of early-onset and/or multiplex diabetes among Chinese patients.</p>

Identification of four novel mutations in the HNF-1A gene in Chinese early-onset and/or multiplex diabetes pedigrees / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Mutations in the hepatocyte nuclear factor-1A gene cause the type 3 form of maturity-onset diabetes of the young (MODY3). This study was undertaken to determine mutations and sequence variations of the HNF-1A gene in Chinese with familial early-onset and/or multiplex diabetes mellitus.</p><p><b>METHODS</b>We screened all ten exons of the HNF-1A gene, including exon/intron junctions, by direct sequencing in 272 unrelated Chinese, including 80 healthy controls and 192 probands of early-onset and/or multiplex diabetes pedigrees.</p><p><b>RESULTS</b>In addition to one silent mutation of c.864 G > C [p.G288G] in exon4 at codon 288, which had been reported previously, a total of four novel mutations including two missense mutations (c.245C > T [p.T82M] and c. 390 G > T [p.Q130H]) and one frameshift mutation P353fsdelACGGGCCTGGAGC and one silent mutation c.759 G > T [p.G253G] were identified. Moreover, eleven substitutions were identified in 192 probands. Of these, three variants (-8 G > A, -128 T > G and IVS2 + 21 G > A) were not observed in 80 healthy controls and one of them (-8 G > A) was not reported previously and the two promoter variants co-segregated with diabetes. The genotype and allele frequencies of the other eight variants in the diabetic patients were not significantly different from those in the healthy controls. No significant relationships were observed between the eight variants of the HNF-1A gene and clinical variables (plasma glucose, insulin, C-peptide and fasting lipid profile).</p><p><b>CONCLUSION</b>The prevalence of structural mutations in the HNF-1A gene responsible for familial early-onset and/or multiplex diabetes appears to be rare among Chinese patients.</p>

Prevalence and clinical characteristics of the A to G variant at position 12026 of the mitochondrial ND4 gene in familial diabetes mellitus in Chinese population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the prevalence of the A to G variant at nucleotide 12026 (mt12026) of the mitochondrial NADH-dehydrogenase subunit 4 (ND4) gene in familial diabetes mellitus in Chinese population.</p><p><b>METHODS</b>The authors screened 770 randomly selected, unrelated probands of diabetic pedigrees, and 309 controls with normal glucose tolerance for the variant by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and PCR-direct-sequencing.</p><p><b>RESULTS</b>The mt12026 A --> G variant was detected in 28 diabetic patients (3.63%) and 9 controls (2.91%). The frequency of the variant mt12026 A --> G was not statistically different between diabetic patients and controls. Moreover, clinical characteristics such as age, body mass index (BMI), and insulin resistant index were not different between diabetic patients with and without the mt12026 mutation.</p><p><b>CONCLUSION</b>The mt12026 A --> G variant is a mitochondrial gene polymorphism in Chinese population, and it is unlikely that the mutation is in itself the cause of diabetes.</p>

Relationship between Leu72Met polymorphism of Preproghrelin gene and type 2 diabetes mellitus and diabetic nephropathy / 上海第二医科大学学报

0.05). Conclusion Preproghrelin-Leu72Met is not significantly associated with T2DM and DN in Shanghai Han populations,while T2DM with AA genotype is characterized by significant declination in urine microalbumin when compared with CA and CC genotypes.Leu72Met polymorphism(C→A)may postpone the development of microalbuminuria in T2DM subjects.

Peroxisome proliferator activated receptor ?2 gene P12A polymorphism and type 2 diabetic nephropathy in Han population in Shanghai / 上海第二医科大学学报

0.05).Frequencies of P12A12 genotype and A12 allele in DN group were significantly decreased respectively,when compared with DN-0 group(for P12A12 genotype,9.1% vs 18.1%,P=0.034,OR=0.453;for A12 allele,4.5% vs 9.0%,P=0.041,OR=0.479). Conclusion The observations suggest that P12A polymorphism of PPAR?2 gene is associated with Chinese type 2 diabetic nephropathy,and A12 allele may protect the development of diabetic nephropathy in type 2 diabetic patients of Chinese.

Relationship between Pro198Leu polymorphism of GPx-1 gene and type 2 diabetes mellitus and diabetic coronary heart disease / 上海第二医科大学学报

0.05).Genotype CT frequency in T2DM group was significantly increased when compared with non-DM control group(P=0.012,OR=2.254).Conclusion Pro198Leu polymorphism of GPX-1 gene increases the risk of type 2 diabetes in Han Chinese of Shanghai,while T allele is not a risk factor of diabetic CHD.

Correlation of Gene Polymorphism of Manganese Superoxide Dismutase and Type 2 Diabetic Retinopathy / 上海第二医科大学学报

0.05).The frequency of VV genotype of Mn-SOD in the DR(+) group was significantly higher than that in the DR(-) group(92.0% vs 77.1%,P

Mutation screening of GCK gene in Chinese early-onset diabetes population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the prevalence of mutations and sequence variations of glucokinase gene GCK in Chinese early-onset diabetes population.</p><p><b>METHODS</b>The study was conducted in 174 unrelated Chinese residents, including 80 nondiabetic controls, 94 probands of early-onset diabetes pedigree. Direct sequencing was performed to screen all 10 exons of glucokinase gene, including promoter and exon/intron junctions.</p><p><b>RESULTS</b>No mutations were identified in coding region, but several previously reported sequence variants were identified. 5'-untranslated region of exon 1a, 84 bp upstream of the translation initiation site GGCGG to GGGGG(early-onset diabetes group G allele frequency 0.106 vs control group 0.075, P=0.355); IVS1b+12 (A-->T) (early-onset diabetes group T allele frequency 0.005 vs non-identity of this variation in control group); IVS 5+29 (G-->T) (early-onset diabetes group T allele frequency 0.027 vs control group 0.019, P=0.731); IVS 9+8 (T-->C) (early-onset diabetes group C allele frequency 0.585 vs 0.694, P=0.044). A novel variation IVS 9+49 (G-->A) (early-onset diabetes group A allele frequency 0.011 vs control 0.006, P=1.000) was identified. There were no significant relationships of the exon 1a 5'-untransted region -84 bp(C-->G), IVS 5+29 (G-->T), IVS 9+8 (T-->C) and IVS 9+49 (G-->A) variants of GCK gene to the clinical variables such as plasma glucose, insulin, C-peptide and fasting lipid profile.</p><p><b>CONCLUSION</b>The prevalence of structural mutations in glucokinase gene responsible for early-onset diabetes appears to be rare among Chinese patients.</p>