Supernumerary chromosome marker Der(22)t(11;22) resulting from a maternal balanced translocation.
Derivative 22 [der(22)] syndrome is a rare disorder associated with multiple congenital anomalies including pre-auricular skin tags or pits, conotruncal heart defects, and profound mental retardation. Der(22)t(11;22) is one of the causes of supernumerary chromosome markers (mar) in humans. We present a boy with developmental delay and multiple anomalies consistent with the supernumerary der(22) syndrome. Cytogenetic analysis showed an abnormal chromosome complement of 47, XY, +mar in all 50 cells analyzed. The karyotype of his mother showed a reciprocal translocation over the distal bands 11q23 and 22q11, respectively, i.e., 46,XX,t( 11;22)(q23.3;q11.2), and that of his father was 46,XY. Thus, the nature of the supernumerary chromosome markers was of der(22)t(11 ;22)(q23.3;q11.2). The clinical features, including craniofacial dysmorphism, hypotonia, psychomotor retardation, heart defects, and urogenital anomalies, were the combined effects of partial trisomies for both distal 11q and pericentromeric 22q.
Hou
Jia-Woei
JW
Division of Medical Genetics, Department of Pediatrics, Chang Gung Children's Hospital, Taoyuan, Taiwan, ROC. houjw741@cgmh.org.tw
D000015:Abnormalities, Multiple / Q000235:genetics*; D002675:Child, Preschool; D002880:Chromosomes, Human, Pair 11; D002892:Chromosomes, Human, Pair 22; D006801:Humans; D008297:Male; D014178:Translocation, Genetic; D014314:Trisomy / Q000235:genetics*