Prenatal Diagnosis of Mosaic Tetrasomy 18p in a Case without Sonographic Abnormalities.

ABSTRACT: Small supernumerary marker chromosomes (sSMC) are still a major problem in clinical cytogenetics as they cannot be identified or characterized unambiguously by conventional cytogenetics alone. On the other hand, and perhaps more importantly in prenatal settings, there is a challenging situation for counseling how to predict the risk for an abnormal phenotype, especially in cases with a de novo sSMC. Here we report on the prenatal diagnosis of a mosaic tetrasomy 18p due to presence of an sSMC in a fetus without abnormal sonographic signs. For a 26-year-old, gravida 2 (para 1) amniocentesis was done due to consanguineous marriage and concern for Down syndrome, based on borderline risk assessment. Parental karyotypes were normal, indicating a de novo chromosome aberration of the

SUBMITTER: Karimzad Hagh J 

PROVIDER: S-EPMC5568194 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature