THE ISOCHROMOSOME-18P SYNDROME - CONFIRMATION OF CYTOGENETIC DIAGNOSIS IN 9 CASES BY INSITU HYBRIDIZATION

Google Scholar
  • 1 September 1990
    • journal article
    • research article
    • Vol. 47  (3) , 493-498
Abstract
Nine cases are described of tetrasomy 18p resulting from the presence of an isochromosome 18p [i(18p)]. The initial diagnosis of i(18p) was by standard cytogenetic techniques and was confirmed by in situ hybridization with a biotinylated alphoid probe (L1.84) specific for the pericentric region of chromosome 18 and with a tritium-labeled chromosome 18 probe (B74) which hybridizes to the D18S3 locus situated at 18p11.3. The clinical features of the cases are summarized and shown to constitute a distinct and recognizable syndrome. Common features were low birth weight, a characteristic facies, neonatal hypotonia with basis of size and cytogenetic handling a marker chromosome can be suspected to be an i(18p). In situ hybridization with the alphoid probe L1.84 provides confirmation of chromosome 18 origin. This more precise diagnosis will be an advantage in situations of pre- and postnatal diagnosis, since parents can be provided with a more confident prognosis for their child.