The Complex Genetic Landscape of Hereditary Ataxias in Turkey and Implications in Clinical Practice. Issue 7 (24th February 2021)

• Record Type: Journal Article
• Authors: Vural, Atay; Şimşir, Gülşah; Tekgül, Şeyma; Koçoğlu, Cemile; Akçimen, Fulya; Kartal, Ece; Şen, Nesli E.; Lahut, Suna; Ömür, Özgür; Saner, Nazan; Gül, Tuğçe; Bayraktar, Elif; Palvadeau, Robin; Tunca, Ceren; Pirkevi Çetinkaya, Caroline; Gündoğdu Eken, Aslı; Şahbaz, Irmak; Kovancılar Koç, Müge; Öztop Çakmak, Özgür; Hanağası, Haşmet; Bilgiç, Başar; Eraksoy, Mefkure; Gündüz, Ayşegül; Apaydın, Hülya; Kızıltan, Güneş; Özekmekçi, Sibel; Siva, Aksel; Altıntaş, Ayşe; Kaya Güleç, Zeynep E.; Parman, Yeşim; Oflazer, Piraye; Deymeer, Feza; Durmuş, Hacer; Şahin, Erdi; Çakar, Arman; Tüfekçioğlu, Zeynep; Tektürk, Pınar; Çorbalı, M. Osman; Tireli, Hülya; Akdal, Gülden; Yiş, Uluç; Hız, Semra; Şengün, İhsan; Bora, Elçin; Serdaroğlu, Gül; Erer Özbek, Sevda; Ağan, Kadriye; İnce Günal, Dilek; Us, Önder; Kurt, Semiha G.; Aksoy, Dürdane; Bora Tokçaer, Ayşe; Elmas, Muhsin; Gültekin, Murat; Kumandaş, Sefer; Acer, Hamit; Kaya Özçora, Gül D.; Yayla, Vildan; Soysal, Aysun; Genç, Gençer; Güllüoğlu, Halil; Kotan, Dilcan; Özözen Ayas, Zeynep; Şahin, Hüseyin A.; Tan, Ersin; Topçu, Meral; Topçuoğlu, Esen Saka; Akbostancı, Cenk; Koç, Filiz; Ertan, Sibel; Elibol, Bülent; Başak, A. Nazlı;
• Is Part Of: Movement disorders. Volume 36:Issue 7(2021)
• Page Start: 1676
• Page End: 1688
• Publication Date: 2021-02-24
• Subjects: ataxia -- genetics -- heterogeneity -- whole‐exome sequencing -- Turkey; Movement disorders -- Periodicals; 610
• DOI: 10.1002/mds.28518
• Languages: English
• ISSNs: 0885-3185

Abstract

Abstract: Background: The genetic and epidemiological features of hereditary ataxias have been reported in several populations; however, Turkey is still unexplored. Due to high consanguinity, recessive ataxias are more common in Turkey than in Western European populations. Objective: To identify the prevalence and genetic structure of hereditary ataxias in the Turkish population. Methods: Our cohort consisted of 1296 index cases and 324 affected family members. Polymerase chain reaction followed by Sanger sequencing or fragment analysis were performed to screen for the trinucleotide repeat expansions in families with a dominant inheritance pattern, as well as in sporadic cases. The expansion in the frataxin ( FXN ) gene was tested in all autosomal recessive cases and in sporadic cases with a compatible phenotype. Whole‐exome sequencing was applied to 251 probands, selected based on the family history, age of onset, and phenotype. Results: Mutations in known ataxia genes were identified in 30% of 1296 probands. Friedreich's ataxia was found to be the most common recessive ataxia in Turkey, followed by autosomal recessive spastic ataxia of Charlevoix–Saguenay. Spinocerebellar ataxia types 2 and 1 were the most common dominant ataxias. Whole‐exome sequencing was performed in 251 probands with an approximate diagnostic yield of 50%. Forty‐eight novel variants were found in a plethora of genes, suggesting a high heterogeneity. Variants of unknown significance were discussed in light of clinical data. Conclusion: With the large sample size recruited across the country, we consider that our results provide an accurate picture of the frequency of hereditary ataxias in Turkey. © 2021 International Parkinson and Movement Disorder Society