Monosomy 5p and partial trisomy 8q due to maternal balanced translocation.

Monosomy 5p (cri du chat syndrome) and partial trisomy 8q are extremely rare events. Here we present a patient with monosomy 5p and distal partial trisomy 8q from a maternal balanced translocation, with clinical observations and cytogenetic studies.The patient was bom to a 26-year-old mother and 27-year-old father after a 38-week gestation at a birth weight of 2,438 g. Both her head and chest circumferences were 29 cm. Her mother had had one previous miscarriage. Signs of slight birth asphyxia were noted at delivery. Multiple anomalies such as microcephaly, high arched palate, hypertelorism, strabismus, epicanthal fold, and micrognathia were recognized. Her extremities showed muscle hypotonia. No major anomalies, including those of the heart, lung and brain were noted. G-banding analysis using peripheral blood revealed a 46,XX,add(5)(pl2). We next performed chromosomal analysis by spectral karyotyping (SKY) using 24-color SKY probes [Applied Spectral Imaging (ASI), Inc., ASI, Carlsbad, CA]. The result of SKY showed 5psyndrome, presumably the distal position of the short arm of chromosome 5 had been replaced by a chromosome fragment of unknown origin (Fig. 1). The parents chose not to undergo chromosomal analysis, so it was not possible at that time to determine the source of the rearrangement. The patient was not able to drink milk orally and she temporarily required tube feeding. Two months after birth she was able to feed orally. Ten months after birth a hearing disorder was corrected with a hearing aid. The mother requested an examination of her own chromosomes for genetic counseling when the patient was 5 years old. The mother's chromosomal analysis demonstrated a balanced translocation between chromosome 5 and chromosome 8.We then performed subtelomeric analysis of patient chromosomes 5 and 8 (Fig. 2A/2B) using fluorescence in situ hybridization (FISH). This analysis showed that the missing derivative chromosome 5 had been replaced by a fragment of the long arm of chromosome 8. In light of the mother's balanced translocation, the patient's karyotype is 46,XX,der(5)t(5;8)(pl2;q24.22)mat (Fig. 3).This is, to the best of our knowledge, the first report of monosomy 5p and distal partial trisomy 8q occurring together in a patient. Trisomy 8q syndrome is relatively frequent among partial trisomy syndromes. The duplication ranges from as long as 8ql3~*qter to as short as 8q21 -* qter (5). Cases of partial trisomy that include 8q 13 have poor life prognosis. On the other hand, the disorder resulting from 8q21->qter is relatively mild. Our reported chromosomal abnormality involving the long arm of 8q24. …