Proximal trisomy 13q and distal monosomy 8p in a dysmorphic and mentally retarded patient with an isodicentric chromosome 13q and a 13q/8p translocation chromosome

A 40 year-old dysmorphic and mentally retarded female is reported with a de novo unbalanced chromosomal rearrangement (karyotype: 46,XX,der(8)t(s;13)( p23;q123),idic(13)(pter-->q123:q123-->pter) resulting in an isodicentric ch romosome 13 and a double aneusomy including. partial trisomy 13 (13pter-q12 3) and distal monosomy 8p (8pter-p23). The main clinical findings consist o f developmental/mental retardation, behavioural disturbances and minor cong enital defects, not consistent with the clinical pattern of either of the t wo aneusomies, A mechanism for the chromosome rearrangement is proposed and the absence of specific physical findings in the present patient is discus sed in the light of the available literature data.