engleski

Familial dic(4 ; 15)(p16 ; q11.1) associated with severe psychomotor retardation

Translocation of 15q11 on to autosomes is a relatively common event, which has no adverse clinical consequence. We report here a case of familial dic (4 ; 15) associated with a severe phenotypic effect. A female neonate who presented with convulsions and a cardial defect showed a satellited chromosome 4 (46, XX, 4ps pat), inherited from her phenotypically normal father. She developed severe psychomotor retardation and epilepsy. The identi.cation of autosomal non-acrocentric breakpoints and the acrocentric donor is often dif.cult. Combined use of conventional and molecular cytogenetics allowed the identi.cation of the unbalanced translocation 46, XX, 4ps pat.ish+15, dic(4 ; 15)(p16 ; q11.1)(D15Z1+, D15S10-, SNRPN-, 4p-, D4Z1+). By FISH the satellited chromosome 4 in the proband and her father was positive with centromere 15 and 4, and negative with probe for Prader/Willi Angelman region and telomere 4. Future molecular characterisation is therefore needed in order to determine a small tandem duplication of DNA within the subtelomeric region, which may have been missed in our case. There is evidence that small chromosomal rearrangements involving the terminal bands of chromosomes are an important unrecognised cause of mental retardation in inherited rearrangements.

Familial 15q11 translocation; Chromosome 4; Chromosome 15

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