[Translocation trisomy 4q in 2 siblings as a sequela of paternal balanced reciprocal translocation: t(1;4)(q44;q31)].

In a sister and a brother with striking similarity of facial dysplasias, severe disturbance of expressive speech, and mild mental retardation a partial trisomy of the long arm of chromosome 4 was identified as cause of these anomalies. The partial trisomy 4q was due to a balanced translocation between the chromosomes 1 and 4 in the father of both children.