Elçin Latife KURTOĞLU, Emine DEMİRAL, İbrahim TEKEDERELİ

Frajil X Sendromu: Moleküler ve Klinik Genetik Yönleri

Frajil X Sendromu, kalıtılabilir zeka geriliğinin en sık sebebidir. Tüm zihinsel gerilik nedenleri arasında da Down Sendromu’ndan sonra ikinci sırada yer almaktadır. Etyolojisinde, X kromozomunun q27.3 bölgesinde bulunan frajil X mental retardasyon 1 (FMR1) geninin 5’ ucunda translasyon olmayan bölgesindeki CGG üçlü nükleotid tekrar sayısının artışı rol oynamaktadır. Bu tekrar artışı aynı zamanda, sitogenetik çalışmalarla gösterilebilen, Xq27.3 bölgesinde kırılganlığa yol açmaktadır. Hastalık fenotipi, kuşaklar arasında ve cinsiyete göre farklılık gösterebilmektedir. Tanısında farklı sitogenetik ve moleküler yöntemler kullanılmaktadır. Bu çalışmada Frajil X sendromunun epidemiyolojisi, klinik özellikleri, tanı yöntemleri ele alınmıştır.

Fragile X Syndrome: Molecular and Clinical Genetics Aspects

Frajil X Syndrome is the most common cause of inherited mental retardation and the second among all intellectual disability causes after Down Syndrome. The increase in the repeat number of CGG triplet nucleotides in the untranslated region at the 5' end of the fragile X mental retardation 1 (FMR1) gene located in the q27.3 region of the X chromosome plays role in the etiology. This repeat increase also leads to fragility in the Xq27.3 region, which can be demonstrated by cytogenetic studies. The disease phenotype may vary between generations and genders. Different cytogenetic and molecular methods are used in the diagnosis. In this study, epidemiology, clinical features, diagnostic methods of Frajil X Syndrome is reviewed.

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