MATERNAL BALANCED TRANSLOCATION LEADING TO PARTIAL DUPLICATION OF 4Q AND PARTIAL DELETION OF IP IN A SON - CYTOGENETIC AND FISH STUDIES USING BAND-SPECIFIC PAINTING PROBES GENERATED BY CHROMOSOME MICRODISSECTION

A 9-month-old boy with pre- and post-natal growth retardation, microce phaly, plagiocephaly, and several minor anomalies had the initial kary otype: 46,XY,der(1)t(1;?) (p36.1;?), Further analysis showed that the der(1) was derived from an unfavorable segregation of a maternal compl ex chromosome rearrangement, i.e., 46,XX,der(1)t(1;?) (p36.1;?), der(4 )t(4;?)(q?;?). Whole chromosome fluorescence in situ hybridization (FI SH) and chromosome microdissection were used to clarify the maternal k aryotype as: 46,XX,der(1)t(1;4)(4qter-->4q33:: 1p36.13-->1qter),der(4) t(1;4)inv(4)(4pter--> 4q31.3::1p36.33-->1p36.13::4q33-->4q31.3:: 1p36. 33-->1pter). Therefore, the karyotype of the boy actually was 46,XY,de r(1)t(1;4) (p36.13;q33). Clinical comparison of the patient's clinical findings showed similarities to individuals with partial del(lp) and dup(4q), To our knowledge the above cytogenetic abnormalities have not been described previously. This case further demonstrates the advanta ges of chromosome microdissection and FISH in the identification of an omalous chromosome regions and breakpoints. (C) 1997 Wiley-Liss, Inc.