Partial trisomy 9p and partial monosomy 6q resulting from paternal reciprocal translocation 6;9: Overlapping manifestations of characteristic phenotypes from birth to age 4 years

We report on a female infant with partial trisomy 9p (p13.3→pter) and monosomy 6q (q26-qter) resulting from a paternal balanced reciprocal traslocation t(6;9)(q26;p13.3). Both trisomy 9p and monosomy 6q are recognized phenotypes with characteristic patterns of anomalies. This patient is the first reported with a partial deletion 6q and a partial duplication 9p resulting in an overlapping phenotype including intrauterine growth retardation (IUGR), craniofacial and skeletal abnormalities, congenital heart defect, hypotonia and developmental delay. We present the clinical follow-up of this patient from birth to age 4 years: the phenotypic manifestations of trisomy 9p syndrome are mildly expressed and many of the clinical signs of monosomy 6q26-qter are present; however the retinal pigmentary degeneration is not apparent (yet). Some additional manifestations (ascites, hydrocephalus, hearing loss) are present which have not been reported in trisomy 9p patients and in terminal monosomy 6q patients. Prolonged follow-up is of value to document the natural history of 9p trisomy and terminal 6q monosomy, allowing for a more accurate diagnosis and refined prognosis of affected individuals