Chromosome abnormalities in pupils attending ESN/M schools.

One hundred and sixty six children attending educationally subnormal/mild (ESN/M) schools were karyotyped as part of a project investigating the aetiology of mild mental retardation. Nine had significant chromosome abnormalities. Five of six children identified during the survey had no dysmorphic features--47,XXY (two), 48,XXYY, 46,XX 15q-, and 46,XX,t(X;19).

The fetal valproate syndrome.

We evaluated seven children who had been exposed to sodium valproate (or valproic acid) in utero. A consistent facial phenotype was observed in all seven in addition to other birth defects in four. The facial changes consisted of epicanthal folds which continued inferiorly and laterally to form a crease or groove just under the orbit, flat nasal bridge, small upturned nose, long upper lip with a relatively shallow philtrum, a thin upper vermillion border, and downturned angles of the mouth.

On the standard error of the probability of a particular diagnosis.

Approximate standard errors of the probability of a particular diagnosis are given for the predictive and estimative methods described by Aitchison and Dunsmore. An example used in the detection of carriers of Duchenne muscular dystrophy (DMD) is given for illustration.

Creatine kinase activity in the detection of carriers of Duchenne muscular dystrophy: comparison of two methods.

Serum creatine kinase activity was estimated in 48 control women and 22 female carriers of Duchenne muscular dystrophy by two different methods. One method is based on the colorimetric determination of creatine liberated from creatine phosphate; the other, an N-acetyl cysteine activated UV system, was used in an automated mode. The two methods were equally efficient in carrier detection, and results were closely correlated over the range of values encountered in controls and carriers.

Dissolution fractions and half-times of single source yellowcake in simulated lung fluids.

Thirty-five samples of yellowcake, the primary product of uranium milling, were obtained from industry. Samples were selected from the archives of 6 yr of yellowcake production from a single uranium milling operation. Ten representative samples were selected on the basis of color variation and chemical composition.

Risks to the offspring of patients with some common congenital heart defects.

The families of 424 adult index patients with ventricular septal defect, right ventricular outflow tract obstruction, or combinations of these two abnormalities, were visited and interviewed, and whenever possible the children of index patients were examined clinically. Congenital heart defects were present in 9 of 308 children, 8 of 899 sibs, 4 of 840 parents, and 4 of 731 nephews and nieces of the index patients. The last three figures are likely to be underestimates owing to the design of the study.

An infant with trisomy 9pter yields 9q22 resulting from 3:1 segregation in a 46,XX t(1;9) (p36;q22) mother.

A newborn infant with a 47,XY,+ der(.),t(1;9) (p36;q22)mat chromosome complement and the clinical features of the 9p trisomy is described. A review of the reproductive histories of five cases with trisomy 9pter yields 9q21 or 22 indicate that the balanced translocation mothers of these infants may have as high as a 23% chance of producing a chromosomally unbalanced offspring due to 3:1 disjunction.

Use of overlapping normal distributions in genetic counselling.

If a numerical variable can be assumed to be normally, but differently, distributed in each of two or more populations, then for an 'unknown' individual whose numerical value is known the relative probability of his belonging to each of the populations can be simply calculated. We briefly review the method and its application in genetic counselling.

Risk of coeliac disease in children of patients and effect of HLA genotype.

Among 73 offspring of parents with coeliac disease, 4 were affected, including 1 in whom the diagnosis was made as a result of the study. The coeliac parents of all 4 were HLA-B8 positive, but 1 affected child had failed to inherit his affected parent's B antigen. The findings are consistent with the hypothesis that an allele affecting liability to coeliac disease is in linkage disequilibrium with HLA-B8.

Duplication 2q33 leads to 2q37 due to paternal ins (12;2) translocation.

An 18 month-old boy with partial duplication of the long arm of chromosome 2, based on a paternal balanced translocation, 46,XY,ins (12,2)( q23;q33q37), is described and compared with five previously reported cases. These children have in common a short nose with broad flat bridge and small anteverted nostrils, long upper lip, low-set ears, and minor digital anomalies.

Use of creatine kinase for detecting severe X-linked muscular dystrophy carriers.

Women thought to be at risk of being carriers of Duchenne muscular dystrophy were given "odds" against their having an affected child. These were calcuated from a combination of the genetic risk from the family history and an estimation of the biochemical risk from measuring the serum creatine kinase concentration. The women were told the actual risk estimate and it was put into perspective for them as a high, medium, or low risk.

The severe recessive form of pseudoachondroplastic dysplasia.

Genetic and clinical heterogeneity within the category of pseudoachondroplastic dysplasia is discussed. Clinical and radiological findings are presented in a family where 4 out of 7 siblings, aged between 3 and 10 years, had a severe form of the condition. The parents had short stature without any signs of pseudoachondroplastic dysplasia.