Ayşegül Yılmaz

Koolen‐de Vries syndrome (KdVS) is a rare multisystemic disorder caused by a microdeletion on chromosome 17q21.31 including KANSL1 gene or intragenic pathogenic variants in KANSL1 gene. Here, we describe the clinical and genetic spectrum of eight Turkish children with KdVS due to a de novo 17q21.31 deletion, and report on several rare/new conditions. Eight patients from unrelated families aged between 17 months and 19 years enrolled in this study. All patients evaluated by a clinical geneticist, and the clinical diagnosis were confirmed by molecular karyotyping. KdVS patients had some common distinctive facial features. All patients had neuromotor retardation, and speech and language delay. Epilepsy, structural brain anomalies, ocular, ectodermal, and musculoskeletal findings, and friendly personality were remarkable in more than half of the patients. Hypertension, hypothyroidism, celiac disease, and postaxial polydactyly were among the rare/new conditions. Our study contributes to the clinical spectrum of patients with KdVS, while also provide a review by comparing them with previous cohort studies.

Genetik bozukluklar; zihinsel yetersizlik ve yaygın gelişimsel gerilik gibi nörolojik tabloların etyolojisinde merkezi bir rol oynamaktadır. Hastaların klinik değerlendirmesi, ayrıntılı öykü ve muayene ile başlayıp, kromozom analizi ve mikrodizin gibi geleneksel yöntemlerden tüm ekzom dizileme gibi ileri moleküler tekniklere kadar uzanan kapsamlı bir tanısal süreci gerektirir. Down, Patau ve Klinefelter sendromları gibi çeşitli kromozomal anomaliler ve mikrodelesyon/duplikasyon sendromları, farklı fenotipik özelliklerle karakterize olup, tanısal süreçte çok disiplinli bir yaklaşımı zorunlu kılar. Güncel moleküler genetik analizler, önceki yöntemlerle tanımlanamayan vakaların aydınlatılmasında kritik bir öneme sahiptir. Genetic disorders play a central role in the etiology of neurological conditions such as intellectual disability and global developmental delay. Clinical assessment requires a comprehensive diagnostic process starting with detailed history and physical examination, followed by advanced molecular techniques ranging from traditional chromosomal analysis to whole-exome sequencing. Various chromosomal anomalies, such as Down, Patau, and Klinefelter syndromes, along with diverse microdeletion and duplication syndromes, present unique phenotypic characteristics that demand a multidisciplinary diagnostic approach. Modern molecular genetic tools are increasingly vital for identifying the underlying genetic causes in cases that remain undiagnosed by standard testing.