Pericentric inversion of chromosome 19 in three families

Monosomy 19pter and trisomy 19q13-qter in two siblings arising from a maternal pericentric inversion: clinical data and molecular characterization

Pericentric inversions of chromosome 19 are very rare rearrangements. Only one case was shown to have resulted in duplication deficiency in the offspring. We report a familial case of pericentric inversion of chromosome 19 not detectable by standard karyotype and usual subtelomeric FISH probes. This inversion was transmitted in its balanced and in its recombinant form to the offspring. The two children carrying the recombinant chromosome 19 presented with growth and mental retardation, microcephaly, mild facial dysmorphism and clinodactyly. The recombinant chromosome 19 was characterized by FISH and array CGH. It consisted of a 400kb 19pter deletion and a 6.9Mb (19q13.33-qter) duplication. This observation supports the recombination risk of pericentric inversion of chromosome 19 and emphasizes the role of molecular cytogenetics techniques in the characterization of chromosome 19 rearrangements.

Duplication 19q13-qter and deletion 19p13-pter arising from an inversion (19)(p13.3q13.3) of maternal origin

Pericentric inversion of chromosome 19 appears to be a rare abnormality with only a few families reported. As far as we are aware, none of them were ascertained because of a recombinant individual. We describe the first identified case due to an affected patient, with duplication deficiency for chromosome 19 arising from a maternal inversion confirmed by FISH and CGH. His features included prenatal growth retardation, microcephaly, dysmorphic facies, congenital heart defect, hypoplasia of corpus callosum and psychomotor delay. The identification of recombinant individuals contribute to calculate a precise risk for inv (19) carriers and to provide a more accurate genetic counselling.