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Özlem Yayıcı Köken

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Review Aug 2026

Congenital myasthenic syndromes in Türkiye: genetic and clinical spectrum revisited in a nationwide pediatric cohort.

Congenital myasthenic syndromes (CMS) are inherited disorders caused by defects in proteins essential for neuromuscular transmission. In this nationwide, multicenter retrospective study, we analyzed 133 genetically confirmed CMS cases from 118 unrelated families between 2017 and 2024 across 28 centers in Türkiye. Clinical, electrophysiological, and genetic data were collected from medical records. In addition, we performed a PubMed-based review of previously reported genetically confirmed Turkish CMS cases to place our findings in a broader national context. The median age at symptom onset, and the median diagnostic delay were 6 months and 24 months, respectively. Ocular involvement was the most common clinical feature, followed by respiratory and bulbar involvement. High consanguinity (82%) contributed to a predominance of homozygous variants. Variants were identified in 16 CMS-associated genes, with COLQ (34.6%), CHRNE (24.1%), and CHAT (12.8%) being the most frequent. Postsynaptic CMS was the most common anatomical subgroup. Eighteen novel variants across 11 genes expanded the mutational spectrum of CMS. Review of 23 previously published studies from Türkiye identified 139 additional genetically confirmed cases, showing a broadly similar genetic distribution, with CHRNE and COLQ predominating, followed by CHAT, whereas other CMS-associated genes were reported only sporadically. >These findings define the clinical and genetic landscape of CMS in Türkiye and, together with previously published Turkish cases, provide a broad national overview based on 272 genetically confirmed cases. The results highlight the major contribution of a limited number of genes and underscore the importance of early molecular diagnosis in a population with high consanguinity.

Canan Üstün, I. Polat, Gülten Öztürk et al. · Neuromuscular Disorders · 0 citations

Case report Open access Sep 2026

Pediatric Familial Cerebral Cavernous Malformation Associated With a Novel KRIT1 Initiation-Region Frameshift Variant.

BACKGROUND Familial cerebral cavernous malformation (CCM) is an autosomal dominant vascular disorder with age-dependent penetrance and marked intrafamilial variability. KRIT1 loss-of-function variants are the most common genetic cause, but pediatric genotype-phenotype correlations remain limited. METHODS Clinical, radiological, histopathological, and molecular findings of a pediatric family with suspected familial CCM were reviewed. Brain and spinal MRI, calvarial histopathology, whole-exome sequencing, segregation analysis, and targeted literature review were performed. RESULTS The index patient was a 14-year-old boy presenting with focal seizure and a progressively enlarging right parietal calvarial mass. MRI revealed multiple cerebral and cerebellar CCMs with a cervical intramedullary cavernous malformation. The calvarial lesion was excised and confirmed as hemangioma. Whole-exome sequencing identified a previously unreported heterozygous KRIT1 initiation-region duplication, NM_004912.4: c.2dup, predicted to result in p.(Met1IlefsTer31) with loss of all major functional domains. The same variant was detected in the clinically asymptomatic sibling with MRI-confirmed multiple CCMs, whereas the mother was negative. The father had died from intracerebral hemorrhage, but genetic testing was unavailable. CONCLUSION This report expands the KRIT1 mutational spectrum and illustrates the wide clinical range of familial CCM, from asymptomatic radiological disease to epilepsy and fatal hemorrhage within one family. These findings support early molecular diagnosis, cascade screening, and susceptibility-sensitive MRI surveillance.

Özlem Yayıcı Köken, M. S. Yanartaş, H. Aygün et al. · Molecular Genetics & Genomic... · 0 citations