Dicentric marker derived from chromosome 22 associated with mild clinical signs: a case report.

Amniocentesis performed after 24 weeks' gestation following ultrasonographic diagnosis of isolated unilateral hydronephrosis showed a de novo extra structurally abnormal chromosome in all cells examined. A combination of conventional and molecular cytogenetic techniques characterized the supernumerary marker as a dicentric and bisatellited marker derived from chromosome 22. At birth the infant presented hypoplasia of the right kidney, hearing loss on the left side and bilateral preauricular pits and skin tags. At three years, growth and neurological development were normal.