KDM5C and paraplegia: The suspicious nonsynonymous hemizygous missense variant carried by the proband KDM5C : NM_004187 : c.1169G > A was also given enough attention, as the KDM5C gene (MIM ∗314690) is associated with X-linked mental retardation (syndromic, ClaesJensen type, MIM #300534) characterized by severe mental retardation, slowly progressive spastic paraplegia, facial hypotonia, and maxillary hypoplasia.