Objective ATN1-related CHEDDA syndrome is a newly described syndromic neurodevelopmental disorder characterized by severe global developmental delay,language deficiency,marked motor disability,dysmorphic facial features,skeletal abnormalities and variable congenital anomalies.Most of the patients also have seizures and structural brain abnormalities. Methods We present the clinical and genetic findings of a first Turkish patient with CHEDDA syndrome. Results A 3 year old boy born from consanguineous parents presented with a complaint of speech and cognitive delay,unsteady gait and seizure.His medical history consistent with truncal hypotonia,autistic features and epilepsy.Physical examination revealed mild facial dysmorphism,autistic features and stereotyped hand movements.All laboratory,metabolic screening tests,genetic test including microarray,karyotype analysis,CDKL15,SLC2A1,and FOXG1 gene analysis were normal.Electroencephalography was compatible with epileptic encephalopathy.The WES (whole exome sequencing) revealed a homozygous four triplets deletion in ATN1 gene(NM001007026.1) which was c.1476_1508del(p.Q492_Q502del) .Parental screening also showed the heterozygosity in both parents for the same variant. Conclusion The universal phenotypic features of CHEDDA are distinctive facial features and global developmental delay are also present in our patient.However our patient has drug resistant epilepsy and epileptic encephalopathy as well as rett like hand stereotypies which further expanded clinical spectrum of CHEDDA syndrome.
Keywords: CHEDDA, epileptic encephalopathy, child ,hand, stereotypies