A de novo translocation of chromosomes 1 and 2 in an 18 year old boy with syndromic mental retardation

Chromosome analysis of cultured lymphocytes from an 18 year old mentally retarded boy with minor dysmorphic features revealed a de novo inverted insertion translocation involving chromosomes 1 and 2. The chromosome complement was interpreted as 46,XY, inv ins(1;2)(q44;p12pter). Parents were phenotypically normal with no chromosomal anomalies.