1, 2 Other examples are those concerning 1q, 3, 4 2q, 5 3p 6. Our presentation highlights the utility of molecular cytogenetic technologies in prenatal diagnosis of rare mosaic chromosome rearrangements and provides evidence for fetoplacental discrepancy under such circumstances. The best-known case is that of the inv dup(8p). Cytogenetic analysis of the extraembryonic tissues revealed the results of 46,XX (40 cells) in placenta, 25% mosaicism (10/40 cells) in amniotic membrane and 50% mosaicism (20/40 cells) in umbilical cord. The 3p deletion syndrome Online Mendelian Inheritance in Man (OMIM) ID 613792 is a contiguous gene syndrome associated with del(3)(p25pter) and the phenotype of mental retardation, IUGR, developmental delay, and craniofacial dysmorphisms of microcephaly, brachycephaly, frontal bossing, triangular face, hypertelorism, palpebral ptosis, hypertrichosis, synophrys, short and thick. The parents elected to terminate the pregnancy, and a malformed fetus was delivered at 24 weeks of gestation with characteristic facial dysmorphism and clinodactyly of the hands. Subsequent fetal blood sampling showed a karyotype of 46,XX,der(3) (qter→q24::p26.3→qter)/46,XX (12.5% mosaicism). Conventional cytogenetic analysis showed a karyotype of 46,XX,der(3)(qter → q24::p26.3 → qter)/46,XX (33% mosaicism). Metaphase FISH analysis revealed 23.3% mosaicism (7/30 cells) in the cultured amniocytes. The presence of a normal cell line in our case is consistent with the postzygotic origin of the recombinant chromosome 3 in the fetus, and provides evidence that deletion-duplication of chromosome. 9q deletion present in mosaic pattern in the mothers.16 Since the. 12 sug-gested that deletion-duplication of chromosome 3 is a result of meiotic recombination. numerous novel microdeletion and microduplication syndromes, which previously. Interphase FISH analysis revealed 27.3% mosaicism (12/44 cells) in the uncultured amniocytes. duplication and partial 3p deletion, Steinbach et al. aCGH analysis detected 0.15-Mb microdeletion of 3p26.3 with CHL1 haploinsufficiency and a 49.42-Mb duplication of 3q24-q29 in the uncultured amniocytes. Array comparative genomic hybridization (aCGH) and interphase fluorescence in situ hybridization (FISH) were applied in the uncultured amniocytes.
A 35-year-old primigravid woman was referred for genetic counseling at 21 weeks of gestation because of 20% (5/25 colonies) mosaicism for add(3)(p26) detected by amniocentesis.