Browsing by Author "Kotan, L. Damla"

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Distribution of Gene Mutations Associated With Familial Normosmic Idiopathic Hypogonadotropic Hypogonadism
(Galenos Yayincilik, 2012) Gurbuz, Fatih; Kotan, L. Damla; Mengen, Eda; Siklar, Zeynep; Berberoglu, Merih; Dokmetas, Sebila; Topaloglu, Ali Kemal
Objective: Normosmic idiopathic hypogonadotropic hypogonadism (nIHH) is characterized by failure of initiation or maintenance of puberty due to insufficient gonadotropin release, which is not associated with anosmia/hyposmia. The objective of this study was to determine the distribution of causative mutations in a hereditary form of nIHH. Methods: In this prospective collaborative study, 22 families with more than one affected individual (i.e. multiplex families) with nIHH were recruited and screened for genes known or suspected to be strong candidates for nIHH. Results: Mutations were identified in five genes (GNRHR, TACR3, TAC3, KISS1R, and KISS1) in 77% of families with autosomal recessively inherited nIHH. GNRHR and TACR3 mutations were the most common two causative mutations occurring with about equal frequency. Conclusions: Mutations in these five genes account for about three quarters of the causative mutations in nIHH families with more than one affected individual. This frequency is significantly greater than the previously reported rates in all inclusive (familial plus sporadic) cohorts. GNRHR and TACR3 should be the first two genes to be screened for diagnostic purposes. Identification of causative mutations in the remaining families will shed light on the regulation of puberty.
Normosmic Idiopathic Hypogonadotropic Hypogonadism Due To a Novel Homozygous Nonsense C.c969a (P.y323x) Mutation in the Kiss1r Gene in Three Unrelated Families
(Wiley, 2015) Demirbilek, Huseyin; Ozbek, M. Nuri; Demir, Korcan; Kotan, L. Damla; Cesur, Yasar; Dogan, Murat; Topaloglu, A. Kemal
ObjectiveThe spectrum of genetic alterations in cases of hypogonadotropic hypogonadism continue to expand. However, KISS1R mutations remain rare. The aim of this study was to understand the molecular basis of normosmic idiopathic hypogonadotropic hypogonadism. MethodsClinical characteristics, hormonal studies and genetic analyses of seven cases with idiopathic normosmic hypogonadotropic hypogonadism (nIHH) from three unrelated consanguineous families are presented. ResultsOne male presented with absence of pubertal onset and required surgery for severe penoscrotal hypospadias and cryptorchidism, while other two males had absence of pubertal onset. Two of four female cases required replacement therapy for pubertal onset and maintenance, whereas the other two had spontaneous pubertal onset but incomplete maturation. In sequence analysis, we identified a novel homozygous nonsense (p.Y323X) mutation (c.C969A) in the last exon of the KISS1R gene in all clinically affected cases. ConclusionsWe identified a homozygous nonsense mutation in the KISS1R gene in three unrelated families with nIHH, which enabled us to observe the phenotypic consequences of this rare condition. Escape from nonsense-mediated decay, and thus production of abnormal proteins, may account for the variable severity of the phenotype. Although KISS1R mutations are extremely rare and can cause a heterogeneous phenotype, analysis of the KISS1R gene should be a part of genetic analysis of patients with nIHH, to allow better understanding of phenotype-genotype relationship of KISS1R mutations and the underlying genetic basis of patients with nIHH.