A maternally inherited balanced reciprocal translocation in a mentally retarded dysmorphic girl

A 29 years old girl with various dimorphic features including short stature and webbed neck with mild to moderate mental retardation was referred to our center for chromosome investigation. Her parents were first cousins. The mother has had two previous miscarriages, one deceased son (12 years old) with apparently similar abnormal features to the proband with congenital heart problems, and one normal son (27 years old). The patient, her mother and the brother, all were found to have an apparently balanced reciprocal translocation between the long arms of chromosomes 4 and 10. The breakpoint on chromosome 4 is at the distal end (4q35), while for chromosome 10, it is proximal to the centromere (10q11.2). FISH studies using multiprobe subtelomeric specific probes as well as whole chromosome paints for chromosomes 4 and 10 were carried out in search of a genetic imbalance. The FISH results revealed no telomeric rearrangements and confirmed the balanced reciprocal translocation between chromosomes 4 and 10. To date, this is the first reported case of t(410)(q35q11.2).