Tetrasomy 18p in two cases confirmation by in situ hybridization.
Two cases with an extra small metacentric chromosome are described. Classic cytogenetic analysis was insufficient for identification of the marker origin. High resolution banding and fluorescence in situ hybridization (FISH) using a chromosome specific painting probe indicated that both marker chromosomes originated from chromosome 18. The correlation between phenotype, cytogenetics and FISH results allowed us to conclude that the patients are tetrasomic for 18p. A comparison of the clinical features of our two patients with other twelve previously reported patients where tetrasomy 18p was confirmed, is also presented.
Departamento de Investigación en Genética Humana, Instituto Nacional de Pediatría, Mexico D.F., México.
M C
MC
Esmer
S
S
Frias
L
L
Gómez
A
A
Carnevale
D000782:Aneuploidy; D002887:Chromosomes, Human, Pair 18; D006801:Humans; D017403:In Situ Hybridization; D007223:Infant; D007621:Karyotyping