Reproductive failure in a carrier of inv dupl l(q21.4----q12).

High resolution analysis of the early metaphase and prometaphase chromosomes of the father of a child with malformations and mental retardation revealed inv dupl l(q21.4----q12). Almost the same was the aberration in the propositus but with a deletion of the band lq11.2 : 46,XX, inv dupl l(q21.4----q12)del lq11.2. This suggested that the malformations and mental retardation in the child were probably due to the microchromosome anomaly in the euchromatin, connected with the heterochromatin block in the father.