Psychomotor development and attention problems caused by a splicing variant of CNKSR2

BACKGROUND: Mutations in CNKSR2 have been described in patients with neurodevelopmental disorders characterized by childhood epilepsy, language deficits, and attention problems. The encoded protein plays an important role in synaptic function. CASE PRESENTATION: Whole-exome sequencing was applied to detect pathogenic variants in a patient with clinical symptoms of psychomotor development, attention deficit, poor logical thinking ability, and an introverted personality, but without epilepsy or any significant electroencephalogram changes. Genetic study revealed a splicing mutation (c.1904 + 1G > A) and RT-PCR revealed aberrant splicing of exon 16, leading to a reading-frame shift and a truncated protein in the PH domain. CONCLUSIONS: This is the first report of a splicing variant of CNKSR2, and the unique clinical features of this pedigree will help extend our understanding of the genetic and phenotypic spectra of CNKSR2-related disorders.