Independent occurrence of de novo HSPD1 and HIP1 variants in brothers with different neurological disorders - leukodystrophy and autism.

Consecutive occurrence of de novo variants in the same family is an extremely rare phenomenon. Two siblings, a younger brother with hypomyelinating leukodystrophy and an elder brother with severe intellectual disability and autistic features, had independent de novo variants of HSPD1 c.139T > G (p.Leu47Val) and HIP1 c.1393G > A (p.Glu465Lys), respectively. These novel variants were predicted to be pathogenic. Both patients also had a known MECP2 variant, c.499C > T (p.Arg167Trp).