Mosaic small supernumerary marker chromosome 1 at amniocentesis: Prenatal diagnosis, molecular genetic analysis and literature review

•We present prenatal diagnosis of sSMC(1) involving 1p21.1-q11.•The analysis was based on aCGH and FISH.•We discuss the genotype–phenotype correlation.•A review of prenatally detected sSMC(1) is presented.

We present prenatal diagnosis and molecular cytogenetic analysis of mosaic small supernumerary marker chromosome 1 [sSMC(1)]. We review the literature of sSMC(1) at amniocentesis and chromosome 1p21.1-p12 duplication syndrome. We discuss the genotype–phenotype correlation of the involved genes of ALX3, RBM15, NTNG1, SLC25A24, GPSM2, TBX15 and NOTCH2 in this case.