A De Novo Unbalanced Translocation t (5;7) (q33;p22) Carrying Partial Trisomy 5q and Partial Monosomy 7p / 대한임상병리학회지

Partial trisomy of the long arm of chromosome 5 distal to 5q33 is rare. Only 16 cases have so far been reported. We report on a three-year-old boy with microcephaly, growth and developmental delay, mild mental retardation, and facial dysmorphism caused by partial 5q trisomy and partial 7p monosomy. The patient has an apparently unbalanced translocation resulting from a rearrangement between chromosomes 5 and 7 (46,XY,der (7)t (5;7) (q33;p22)de novo). Fluorescence in situ hybridization with chromosome 5 and 7 painting probes and a cri-du-chat critical region probe confirmed this chromosome rearrangement. Most cases of partial trisomy 5q33-q35 described to date are due to the unbalanced transmission of a familial translocation. To the best of our knowledge, there are no previous reports of de novo unbalanced translocations of these two chromosome abnormalities together with similar breakpoints.

An unusual combination of trisomy 21 and partial trisomy 5q

The authors describe a male newborn with multiple congenital anomalies; craniofacial dysmorphism, bilateral cleft palate and lip, ambiguous external genitalia with absence of phallus, ventricular septal defect, agenesis of olfactory bulbs, and presence of small round cells simulating migration defect in the cerebellar white matter. Cytogenetic study demonstrated a chromosomal constitution of 47,XY, +21, +5q. Its pathological significance compared with Down's syndrome and hitherto reported partial trisomy 5q is discussed.