Severe phenotype in a girl with partial tetrasomy 7, karyotype 46,XX,trp(7)(q35q36)

On prenatal ultrasonography, polyhydramnion, internal hydrocephalus, hypoplasia of the corpus callosum, and dysmorphic features were detected in a fetus of a 22-year-old mother. Subsequent karyotyping of amniocytes revealed supernumerary material in distal 7q. The baby was delivered after 38+4 weeks of gestation, and postnatal array CGH analysis showed a triplication of 7q35-->q36, resulting in partial tetrasomy. The triplication was not distinguishable from a duplication by conventional and molecular cytogenetic methods, but was clearly identified by array CGH analysis. The phenotype was rather severe with limited cardiac contractility and subsequent respiratory problems, as well as progressive neurologic deterioration and several dysmorphic features. Triplications in general are rare, and this case is the first report of a microscopically visible triplication in 7q. Duplication patients of the same chromosomal segment also showed a severe phenotype, however, in our opinion there are no common features suggesting a clinically recognizable distal 7q duplication/triplication syndrome.