Re-understanding autism: Fractionable symptoms and quantitative genetics

Öz

Autism spectrum disorder is diagnosed based on impairments in social interaction and communication and engagement in restricted and repetitive behaviors and interests. Understanding the etiology of autism and developing effective interventions can be challenging due to the disorder's complex and heterogeneous nature. The search for a single cause for autism may be the reason for limited progress in the relevant research. The “fractionable autism triad" hypothesis suggests that the symptom domains defining autism are largely independent of each other at behavioral, cognitive, neural, and genetic levels. This paper outlined the evidence for the hypothesis at the genetic level using quantitative genetic methods. Results suggested that genetic factors associated with autism symptoms may differ, giving support to the fractionable autism triad hypothesis. The phenotypical variance within monozygotic twin pairs, lack of plausible associations between the levels of core symptom domains, and differences in genetic and/or environmental factors contributing to different symptom groups indicated the independence of the triad. These findings, which were discussed with limitations and suggestions for future research, are illuminating the heterogeneity of the disorder and lead researchers to new directions for the development of interventions tailored to specific difficulties. This way, treatment protocols can be developed for individuals with difficulties in specific symptom groups and those who could not meet the diagnostic criteria but continue having related difficulties.

Anahtar Kelimeler

• autism spectrum disorder
• autism symptoms
• fractionable autism triad
• quantitative genetics

Otizmi Yeniden Anlamak: Parçalanabilir Belirtiler ve Nicel Genetik

Öz

Otizm spektrum bozukluğu, sosyal etkileşimde ve iletişimde güçlükler ile kısıtlı/tekrarlayan davranışlar ve ilgi alanları temelinde tanımlanmaktadır. Otizmin etiyolojisini anlamak ve etkili müdahale yolları üretmek, bozukluğun karmaşık doğası ve belirtilerin farklı şekillerde görülebilmesi gibi sebeplerden dolayı zorlayıcı olabilmektedir. Konu hakkında kısıtlı ilerlemenin sebeplerinden biri birbirinden oldukça farklı belirti gruplarını açıklayan tek bir sebep aranması olabilir. Parçalanabilir otizm üçlemesi hipotezi, otizmi karakterize eden belirti gruplarının davranışsal, bilişsel ve genetik düzeylerde büyük ölçüde birbirinden bağımsız olabileceğini önermektedir. Bu makale, söz konusu hipoteze kanıt teşkil edebilecek nicel genetik yöntemler ile elde edilen bulguları değerlendirmeyi amaçlamaktadır. Söz konusu bulgular, otizm belirtilerinin genetik temellerinin farklılık gösterebildiğine işaret etmekte ve parçalanabilir otizm üçlemesi hipotezini desteklemektedir. Tek yumurta ikizlerinde görülen fenotipik varyanslar, belirti grupları arasında yeterli düzeyde anlamlı ilişkinin bulunamayışı ve hem genetik hem de çevresel faktörlerin etkisi açısından tespit edilen farklılıklar otizm belirtilerinin birbirinden bağımsız değerlendirilebileceğine işaret etmektedir. Belirli kısıtlılıklar ve bunlara yönelik öneriler ışığında tartışılan bulgular otizmin heterojen yapısını anlamayı kolaylaştırmakta ve etkili müdahale teknikleri geliştirilebilmesi için yol göstermektedir. Böylece, belirli belirti gruplarında daha çok güçlüğü bulunan otizm tanısı almış bireyler kadar tanı kriterini karşılayacak kadar çeşitli belirtilere sahip olmayan ancak yoğun güçlük yaşayan bireyler için faydalı olacak müdahale protokollerinin oluşturulabileceğine dikkat çekilmiştir.

Anahtar Kelimeler

• otizm spektrum bozukluğu
• otizm belirtileri
• parçalanabilir otizm üçlemesi
• nicel genetik

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