Molecular identification of a small supernumerary marker chromosome by in situ hybridization: diagnosis of an isochromosome 18p with probe L1.84

Abstract
A dysmorphic child was found by cytogenetic analysis to have an extra small marker chromosome. The marker chromosome was shown to possess a chromosome 18 centromere by in situ hybridization, and probably represents an isochromosome 18p. Centromere specific probes should be of value in identifying extra small marker chromosomes, and thereby provide better understanding of the clinical significance of these.