A study of mental retardation in children in the Island of Hawaii

Abstract

Eighty‐one probands from an initial population of 223 school‐aged retarded individuals were assessed by history, clinical examination and, where appropriate, cytogenetic analysis. In 51 individuals, the retardation occurred as an isolated event within the family, whereas 30 patients had a family history of retardation. In 39 of the isolated individuals, the retardation was either related to environmental factors or associated with a major neurological abnormality. The remaining 12 patients were phenotypically normal with no cytogenetic abnormality. Of the 30 probands from 15 families with a history of retardation, 3 families had X‐linked syndromes. One, with 4 proband daughters, had the mar(X) syndrome and two families were considered to have the phenotypically similar syndrome but without demonstrating the mar(X). In an additional 5 families, the distribution and clinical features of the affected individuals were compatible with nonspecific X‐linked mental retardation.

Mutations in the BRWD3 Gene Cause X-Linked Mental Retardation Associated with Macrocephaly

“…8 Relative macrocephaly and short stature are also features of MRX2, which has been mapped to Xq22. 9,10 Here, we describe two families with mental retardation and macrocephaly and an X-linked pattern of inheritance. In each family, we have identified a different protein-truncating mutation in the BRWD3 gene (MIM 300553), located at Xq21.1.…”