A new case with coexistence of mosaic 48,XYYY/47,XYY, and CACNA1E variant in autism spectrum disorder.

Autism spectrum disorder (ASD) is a genetically heterogeneous neurobehavioral disorder. The etiology and the inheritance pattern are usually multifactorial. The index case is a 3-year-old male, whose family applied to the child psychiatry outpatient clinic due to failure to speak at 30 months. He had mild dysmorphic features. He is diagnosed with ASD according to DSM-V criteria. Chromosomal analysis revealed mos 48,XYYY[28]/47,XYY[72] karyotype. In FISH analysis, nuc ish (DXZ1x1, DYZ1x3)[44]/(DXZ1x1, DYZ1x2)[156] was detected. WES results displayed a heterozygous missense variant of uncertain significance c.3545G>A in the CACNA1E gene. XYY syndrome is one of the most common sex chromosome aneuploidies, and ASD is detected 20 times more likely than males in general population. To the best of our knowledge, the first case with the coexistence of mosaic 48,XYYY/47,XYY karyotype and CACNA1E variant together may contribute to phenotypic heterogeneity. Further investigation into the functionality of the variant in CACNA1E is needed.