A fourteen years follow-up of a case of partial trisomy 12q and monosomy 12p recombinants of a familial pericentric inversion of chromosome 12: clinical, cytogenetic and molecular observations.

Partial trisomy 12q and monosomy 12p lead to multiple malformation syndromes. Only four cases were previously reported with the association of these two aneusomies resulting from a familial pericentric inversion of chromosome 12. We report on the clinical, cytogenetic and molecular findings in a boy with an unbalanced karyotype which resulted from a familial pericentric inversion of chromosome 12. The patient was evaluated at birth and followed up until 14 years of age. He showed severe mental retardation, seizures, and dysmorphic features related both to a trisomy 12q and a monosomy 12p. Chromosome breakpoint BAC-FISH mapping revealed that the rec(12) chromosome had a terminal deletion of a 6.7Mb region extending from 12pter to 12p13.31 and a duplicated region of 19.8Mb extending from 12qter to 12q24.13. The findings from the case reported here emphasize the occurrence of some consistent clinical features and illustrate the deficiencies associated with the recombinants from the inversion inv(12)(p13.31q24.13)mat.