A case of 48,XXXX female with normal intelligence.

Mental retardation has fequently been noted in patients with extra sex chromosomes. The following case report details a girl with 48,XXXX sex chromosome constitution and normal intellectual potential. Case Report The patient was first seen at age 3 years 9 months because of slow development of speech. She was the second child of a 25-year-old mother who had a normal pregnancy, labour, and delivery. Birth weight was 2892 g. The father was 28 years of age. There are two female sibs, aged 6 and 2 years, and both are in good health. No miscarriages are reported. Physical examination revealed an attractive child who was 88 cm tall and weighed 13-7 kg, both of which were within the lower 20th centile for her age and sex. She had epicanthal folds, incurved 5th fingers, widely-spaced nipples, and bilateral external tibial torsion. Her speech was unclear but she related warmly and appropriately to the examiner. Because of the speech difficulty language, speech, and hearing were evaluated. On audiometric screening, hearing was judged normal in both ears. The patient was found to have a severe articulation problem with a delay in both receptive and expressive language. the physical examination. Despite her indistinct speech, she scored a mental age of 3 years 9 months (IQ 100) on the Stanford-Binet Intelligence Scale, Form L-M. Followup testing at age 5 years showed the patient to be functioning within the normal range using the Wechsler Intelligence Scale for Children: verbal IQ= 106, performance IQ= 94, full scale IQ= 101; mental age = 5 years 1 month. Laboratory studies included normal skull films, PBI, urinalysis, CBC, and Guthrie test. A 24-hour urine screen for amino acids was normal and the turbidity test for mucopolysaccharides was negative. Cytogenetic Studies. Leucocyte culture of peripheral blood was performed by standard methods. Fifty cells were counted and the chromosome complement was 48 with no evidence of mosaicism, and the extra chromosomes were in the C group (Fig. 1). Buccal smear on two occasions showed the presence of up to 3 Barr Bodies (Fig. 2) compatible with tetra X chromosome constitution. The detailed buccal smear studies are summarized in Table I. Skin biopsy was requested but not granted. Chromosome analysis of peripheral leucocyte culture from each parent showed normal chromosome complement. The dermatoglyphic pattern of the patient was analysed and is shown in Table II. The unusual features include low ridge count, radial loop …