Polymorphisms in Turkish population

Department of Medical Biology, Faculty of Medicine, Suleyman Demirel University, 32260 Cunur, Isparta, Turkey, nilufersahin@yahoo.com.

Mutations in the ganglioside-induced differentiation-associated protein 1 gene (GDAP1) cause Charcot-Marie-Tooth type 2 (CMT2), a severe autosomal recessive form of neuropathy associated with axonal phenotypes. It has been screened in this study for the presence of mutations in the coding region of GDAP1, which maps to chromosome 8q21, in a family with CMT2. To date, 29 mutations in the GDAP1 have been reported in patients of different ethnic origins. Here, we report a novel missense mutation (c.836A>G), and two polymorphisms: a silent variant (c.102G>C), and a 5′-splice site mutation (IVS5+24C>T) in GDPA1 gene identified in a five generation Turkish family with autosomal recessive CMT2.

Department of Medical Biology and Genetics, Gazi University Faculty of Medicine, Besevler, Ankara, Turkey. erkan_yurtcu@yahoo.com

Obesity is a complex disease caused by both genetics and environmental factors. Melanocortin-4 receptor (MC4R) (MIM 155541) gene polymorphisms were reported to be the cause of monogenic obesity in humans. We studied three polymorphisms (Val50Met, Val103Ile, and Ser58Cys) and a mutation (Asn274Ser) of the MC4R gene in 203 obese patients and in 110 healthy subjects in the Turkish population. A high incidence of Val103Ile and Val50Met polymorphisms as well as the Asn274Ser mutation was found in the obese patients, whereas no significant correlation was found regarding the Ser58Cys polymorphism. We conclude that there is a concordance between the polymorphisms (Val103Ile, Val50Met, Ser58Cys) that were first studied in the Turkish population with obesity.

Department of Endocrinology and Metabolic Diseases Department, Ankara University School of Medicine, Ibni Sina Hospital, Ankara, Turkey. drsahinmustafa@yahoo.com

We previously shown that in a Turkish population, the A/G polymorphism in exon 1 of the cytotoxic T cell lymphocyte-associated molecule-4 (CTLA-4) gene is associated with Graves’ disease, and that the G allele may contribute to susceptibility for developing Graves’ disease. This polymorphism was identified in 197 patients with Hashimoto thyroiditis (HT) (126 women, 71 men; aged, 42.92 +/- 13.4 years) and 98 healthy individuals (56 women, 21 men; aged, 42.27 +/- 13.43 years) in Turkish population. Polymorphisms were analysed using a polymerase chain reaction-restriction fragment length polymorphism method. Frequency of the A/G genotypes was not significantly different in patients with HT when compared with controls in both sexes (P > 0.05). There was no statistical difference in age, sex, cigarette smoking, initial serum thyroid hormone levels, initial goiter size and thyroid autoantibodies among the patients with the three different genotypes (G/G, A/G and A/A). We concluded that A/G polymorphism of CTLA molecule is linked to occurrence of Graves’ disease bu not to HT in the Turkish population.