Mosaic tetrasomy 8q: Inverted duplication of 8q23.3qter in an analphoid marker

We observed an analphoid marker chromosome stable through cell division in a 16-year-old girl with developmental delay, short stature, limb contractur es, and ovaries containing multiple cysts, She also developed myasthenia gr avis at 15 years. The marker chromosome, present in 75% of metaphases land in 90% Of transformed lymphoblastoid cells), was C-band negative, and had n o pan cy-satellite sequences detectable by fluorescence in situ hybridizati on (FISH), The 8q origin of the marker was determined by use of subtelomeri c probes and was confirmed by chromosome 8 painting probes. The marker was shown to be an inversion duplication of 8q when subtelomeric, telomeric, an d c-myc FISH probes hybridized to both ends of the marker, The karyotype wa s 47,XX,+inv dup(8)(qter --> q23.3::q23.3 -->[neocen]-->qter), resulting in tetrasomy for 8q23,3qter, The parents had normal karyotypes, Centromeric p roteins CENP-C and CENP-E were present, but alpha associated centromere pro tein CENP-B was absent at a position defining a neocentromere, Am. J, Med, Genet. 92:69-76, 2000, (C) 2000 Wiley-Liss, Inc.