Dikkat Eksikliği Hiperaktivite Bozukluğunun Genetik Boyutu

Dikkat Eksikliği Hiperaktivite Bozukluğu (DEHB) çocukluk çağının en sık görülen nöropsikiyatrik bozukluklarından biridir. DEHB tanısının etkilerinin yaşam boyu devam edebileceğini bildiren çalışmalar nedeniyle çocuk ve ergen ruh sağlığında büyük önem taşıyan bu bozukluk, son dönemde erişkin psikiyatrisi açısından da ilgi toplamaya başlamıştır. Bu yazıda dünyada ve ülkemiz-de giderek daha çok ilgi toplayan DEHB'nin genetik boyutları hakkında yürütülmüş olan araştırmaların sonuçlarını değerlendirilmesi hedeflenmiştir. Bu amaçla PubMed ve Türk Psikiyatri Dizini gibi çevrimiçi arama motorları taranmış, elde edilen veriler temel kitaplardaki bilgilerle birleştirilmiştir. Yapılan çalışmalar DEHB'nin psikiyatrik bozukluklar içerisinde en yüksek genetik özelikle gösteren bozukluklardan biri olduğunu göstermektedir. Tanı ve tedavi açısından önemine rağmen, DEHB'nin etiyolojisi çok iyi aydınlatılamamıştır ve bozukluk hem genetik hem çevresel faktörlerin etkisiyle ortaya çıkan karmaşık bir problem gibi gözükmektedir. Geçmiş çalışmalarda DEHB'nun ailesel ve kalıtımsal geçiş gösterdiği saptanmışsa da diğer çoğu psikiyatrik bozuklukta olduğu gibi, soy ağaçlarının incelenmesi tutarlı bir Mendelyen kalıtım biçimi göstermemiştir. Bu nedenle son yıllarda DEHB'nin moleküler genetik temeli konusunda çok sayıda çalışma ortaya çıkmıştır. DEHB'den sorumlu olan genleri araştıran çalışmaların sonuçlarının birbirleriyle tam olarak örtüşmemesinin bozukluğun heterojenliğine ve istatiksel sınırlılıklara bağlı olduğu düşünülmektedir. Bu sınırlamaları aşabilmek için genetik çalışmalarda hastaların DSM-IV alt tiplerine göre değil, eş tanı ve ergenlikteki devam edip etmemelerine göre gruplandırılmaları önerilmektedir.

Genetic Basis of Attention Deficit Hyperactivity Disorder

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common neuropsychiatric disorders of childhood. Due to studies reporting that the effects of ADHD diagnosis on functioning may last throughout life, this disorder, which has great importance for child and adolescent psychiatry, started to attract greater attention recently in terms of adult psychiatry. A review, evaluating the results of studies conducted on the genetic basis of ADHD, which started to attract increasing attention both in our country and the world, was thought to help clinicians working in this field. PubMed and Turkish Psychiatry Index online search engines were screened using "attention deficit hyperactivity disorder", "ADHD", "genetics" as key words. The data obtained were combined with information gleaned from several textbooks. Based on previous studies, it could easily be concluded that ADHD is one of the most common heritable psychiatric disorder with distinguished genetic features. Despite its importance for diagnosis and treatment, the etiology of ADHD is still not clear and the disorder seems to be a complex problem arising from the effects of both genetic and environmental factors. Although previous studies revealed that ADHD displayed familial and hereditary transmission, stable patterns of Mendelian inheritance could not be discriminated by evaluation of pedigrees. Therefore, many studies have been conducted on the molecular genetic basis of ADHD recently. The previous studies did not report consistent results in identification of the genes responsible for ADHD which has been partially linked to heterogeneity of the disorder. Grouping relevant patients according to comorbidities and persistence in adolescence rather than DSM-IV subtypes could be an important alternative method for overcoming this limitation in the research studies.

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