Prenatal diagnosis and molecular characterization of an interstitial 1q24.2q25.2 deletion

We report on the observation of an interstitial deletion of the long arm of chromosome 1 diagnosed prenatally in a 28 weeks gestation fetus by standard karyotype. Amniocentesis was performed because of an increased Down syndrome maternal serum screening and ultrasonographic abnormalities. Fetus autopsy showed an intrauterine growth retardation, dysmorphic features and limbs abnormalities. Using fluorescent in situ hybridization technique (FISH), we characterized the deletion boundaries corresponding to the bacterial artificial chromosomes (BAC) RP11-193J5 and RP11-162L13. Molecular studies identified the deletion of paternal origin. Therefore the karyotype was interpreted as 46,XY,del(1)(q24.2q25.2). This is the smallest deletion of the long arm of chromosome 1 reported prenatally and characterized at the molecular level. Its phenotype is compared to other similar cases described in the literature.