First Turkish case with UNC80 deficiency

Objectives The UNC80 gene encoded protein has an important role in the functioning of a sodium channel called NALCN channelosome in the cell membrane of nerve cells (neurons). UNC80 deficiency characterized by hypotonia,developmental delay,intellectual disability,intrauterine growth retardation, seizures severe constipation, feeding difficulties and failure to thrive with characteristic facial features. Joint deformities, repetitive movements, and nystagmus can be seen occasionaly. Methods Herein we present the first Turkish case with UNC80 deficiency. Results A 6-year and 9-month-old male patient presented with hypotonia at the age of one year. His medical history was unremarkable. He was able to sit at 10 months-old and walk at 16 months-old. On physical examination, he had significant axial hypotonia, failure to thrive and dysmorphic features such as frontal bossing and bullous nasal structure. Laboratory evaluation revealed persistent high transaminase levels. Liver biopsy was performed for increased transaminase levels and it showed normal structure. His lysosomal enzyme scanning, brain MRI and spectroscopy were normal. No mutations were found in NPC1, NPC2 and Gaucher genes analysis. A homozygous c.840C>G p.(Ile280Met) mutation was detected in UNC80 gene on whole exome sequencing . Conclusion To our knowledge,this case is the first Turkish patient with UNC80 deficiency syndrome.In addition, he was also the first reported patient with UNC80 deficiency who had transaminase elevation. This was expanded the clinical spectrum of the syndrome.
Keywords: UNC80, failure to thrive, hypotonia, NALCN, speech delay, elevated transaminase