Unbalanced 4;6 translocation and progressive renal disease.

Two sibs are described with an unbalanced 4;6 translocation resulting in partial trisomy 6p and monosomy for distal 4p. Growth retardation, psychomotor retardation, and characteristic facial appearance are present. The facial anomalies include high prominent forehead, blepharoptosis, blepharophimosis, high nasal bridge, bulbous nose, long philtrum, small mouth with thin lips, and low-set ears. Both children have small kidneys and have had proteinuria since early childhood. The older boy developed progressive renal disease including hypertension and renal failure necessitating renal transplantation at age 18 years. Renal biopsy of the younger girl also indicates significant renal involvement. Progressive renal disease is likely an important part of the trisomy 6p phenotype.