Pure 6p22-pter trisomic patient: refined FISH characterization and genotype-phenotype correlation.
First described in 1971, partial trisomy 6p is uncommon and generally secondary to a familial reciprocal translocation. The proximal breakpoint of the reported cases varies from p11 to p25. We here report on a patient with moderate mental retardation, craniofacial and pigmentary anomalies, proteinuria, and hyperglycemia who was found to have a mosaic karyotype 46,X,add(Y)(q12)/45,X. Fluorescence in situ hybridization (FISH) enabled us to identify that the additional material on Yqh derived from 6p and to define the rearrangement as der(Y)t(Y;6)(q12;p22). To the best of our knowledge, this is the first case of trisomy 6p22-pter without an associated deleted segment; the second breakpoint of the rearrangement is in Yqh. Precise mapping of the centromeric breakpoint of the trisomic 6p segment allowed a more convincing correlation between partial 6p trisomy and clinical phenotype to be addressed. In particular, the proteinuria often observed in 6p trisomic patients could be assigned to the 6p22-6pter region.
Giardino
D
D
Laboratorio di Citogenetica, Istituto Auxologico Italiano, Milan, Italy. giardino@auxologico.it
Finelli
P
P
Caufin
D
D
Gottardi
G
G
Lo Vasco
R
R
Turolla
L
L
Larizza
L
L
D002896:Chromosomes, Human, Pair 6; D005838:Genotype; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D010641:Phenotype; D014178:Translocation, Genetic; D014314:Trisomy; D014998:Y Chromosome