Genetic counseling of mosaicism for a deletion due to partial monosomy in a cell line with 46 chromosomes associated with a normal cell line at amniocentesis

Genetic counseling of mosaicism for a deletion due to partial monosomy in a cell line with 46 chromosomes associated with a normal cell line at amniocentesis remains difficult because mosaic deletion due to partial monosomy has been reported to be associated with either normal or abnormal phenotype in prenatal diagnosis. This article makes a comprehensive review of the reported cases of mosaicism for a deletion due to partial monosomy in a cell line with 46 chromosomes associated with a normal cell line at amniocentesis and various counseling issues such as culture artefact, cytogenetic discrepancy between cultured and uncultured amniocytes and among various tissues, perinatal progressive decrease of the abnormal cell line and a possible favorable fetal outcome. The information provided is useful for obstetricians and genetic counselors during genetic counseling of the parents who wish to keep the babies under such a circumstance.