Genetic studies in mental subnormality.

Date:
1973
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Genetic studies in mental subnormality. Source: Wellcome Collection.

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    €8 GENETIC STUDIES IN MENTAL SUBNORMALITY walk only with sticks and the youngest unable to walk even with support. They all have short fingers and toes. The •eldest has webbing of the toes; the youngest has dystrophic finger nails and juvenile blue ■dot cataracts. The E.E.G.s had a generalized abnormality which was similar in the affected siblings. Biochemical and radiological investigations were normal. Inheritance: consistent with recessive auto¬ somal form. Family 6—Major epilepsy, psychosis, asymmetry The sibship consists of a normal sister aged 29, a sister (index case 13) aged 27, a sister (index case 14) aged 25 and a normal brother •aged 24. The parents are of normal intelligence and unrelated. The mother's only sister has epilepsy and the maternal grandfather 'died in a mental home'. No further information con¬ cerning the family is known. I.Q.s have not been formally assessed but we have estimated that they are 15 or less. Neither of the affected siblings is able to speak. They are antagonistic, unable to co-operate and ■divorced from their surroundings, aimlessly rushing about. Major epileptic attacks occur in both. The only physical abnormalities, apart from short limbs, are asymmetry of the face and orbits. The elder (case 13) also shows asymmetry of the breasts, and the younger (case 14) asymmetry in circumference but not length of the thighs. In both the asymmetry is character¬ ized by larger size of the right side. Biochemical investigations were within normal limits. E.E.G.s were not performed. Mode of inheritance: consistent with auto¬ somal recessive form. Family g—Fair hair, wide mouth, dwarfism, regurgitation, abdominal distension, abnormal derma- toglyphics, abnormal skin pattern Of the two brothers (index cases 19 and 20) born in 1951 and 1953, the elder died of maras¬ mus and has not been fully investigated. They have normal twin brothers aged 10. The parents are unrelated ; the mother is of 'low intelligence' and is short (height 137*2 cm.) and weighs 42-6 kilo. She has small hands and minor digital anomalies. Her birth weight was i • 8 kg. The maternal grandmother was also short (height 152-4 cm.). No other instance of dwarfism or severe subnormality is known in the parents, 16 siblings or in cousins. Births and neonatal periods were normal. The older brother (case 19) was first seen on account of severe vomiting, abdominal disten¬ sion and severe mental retardation at the age of 4 years. At 8J years he weighed 12-5 kilo. His I.Q. was not estimated formally but we assessed his mental age to be approximately б months. Undisturbed he was somnolent, but had frequent regurgitations, and lay in the foetal position. He had fair hair, severe wasting, growth retardation and gross abdominal disten¬ sion. No other clinical abnormality was detected, apart from increased tone and exaggerated knee and ankle reflexes. His bone age was 3^ years (chronological age 8^ years). There was no biochemical evidence of hypothyroidism. Serum cholesterol 120 mg./ioo ml. (normal). Serum lipoproteins normal. He died at 12 years of age. Postmortem examination revealed nothing unsuspected, and routine histology was normal, but brain histology was not performed. The younger brother (case 20) had a mental age of I year (chronological age 16) and was usually lying in the foetal position. Weight 16-7 kilo; height 104 cm.; head circumference 50 cm. Like his brother he had severe wasting, growth retardation, abdominal distension and frequent regurgitation. The last is now less persistent and there has been considerable improvement in nutrition during the last four years. He closely resembles his brother in facial appearance, fine fair skin and hair, unhappy expression and wide mouth. All fingers show arches. The skin of the lower thorax shows a pattern of fine transverse striations о •7-1 mm. in width. No other abnormal physical signs were detected. Biochemical investigations showed no ab-