A cytogenetic study of nonpolymalformed patients with mental retardation of clinically undefined etiology: application of a high resolution banding technique.

We performed a cytogenetic study on 140 nonpolymalformed patients with mental retardation of clinically undefined origin, using a high resolution banding technique, to determine how much chromosome abnormalities contribute to the etiology of this condition. A total of 15 patients (10.7%) were found to have autosomal or sex chromosomal abnormalities. Autosomal abnormalities included partial monosomy (5 cases), reciprocal translocation (one case), 13/14 robertsonian translocation (3 cases), unbalanced translocation (one case), inverted duplication of 15q (one case) and mosaic trisomy 21 (one case). Sex chromosomal abnormalities comprised structural rearrangement of the short arm of the X chromosome (one case) and 47, XXY in a pure or mosaic form (two cases). It should be noted that four out of the 5 cases of partial monosomy had subtle interstitial deletions, which might have been unidentified by the conventional G-banding method alone. In one case of the robertsonian translocation 46,XY,t(13;14)/45,XY,t(13;14), a small deletion was thought to have occurred in the cells with a chromosome number of 45. Comparison of clinical features of the 15 chromosomally abnormal patients with those of patients with normal karyotypes did not show any clinical parameter indicative of chromosome imbalance. These results suggest that a subtle chromosomal deletion is specific to mental retardation associated with few malformations. We believe that diagnostic evaluation of mentally retarded patients, even if nonmalformed, should include chromosome analysis using a high resolution banding technique.</p

Multivariate analysis of dermatoglyphics of severe mental retardates: an application of the constellation graphical method for discriminant analysis.

We studied the dermatoglyphics of 353 severe mental retardates (excluding those with chromosomal abnormalities and major limb malformations), using multivariate analysis, to determine how early intrauterine factors are related to the etiology of mental retardation. First, dermatoglyphics were compared between 140 individuals with undefined prenatal factors and 700 normal controls. After 6 and 9 dermatoglyphic traits were chosen as discriminative variables for males and females, respectively, the data were subjected separately for each sex to the constellation graphical method for discriminant analysis. The same formula as obtained in the idiopathic group was subsequently applied to data from cases in other etiological categories. When the misclassification rate was 0.03, the rates of correct classification of the male patients into the etiological categories of undefined prenatal, defined prenatal, perinatal, postnatal and unknown (no anamnestic data available) categories were 19.7% (13/66), 20.0% (3/15), 8.8% (5/57), 5.0% (1/20) and 7.7% (2/26), while the correct classification rates of females were 24.3% (18/74), 42.1% (8/19), 18.9% (7/37), 5.1% (1/16) and 13.0% (3/23), respectively. The results suggest that early intrauterine factors such as those producing dermatoglyphic deviations may contribute to the pathogenesis of severe mental retardation not only in patients with undefined prenatal etiological factors but also in those with perinatal factors, especially those of the female sex.</p

Detection of hepatitis B surface antigen subtype adr in an epidemic of papular acrodermatitis of childhood (Gianotti's disease).

Papular acrodermatitis of childhood (PAC) has recently been reported to be associated with hepatitis B surface antigen (HBsAg) subtype ayw. Between September, 1978, and June, 1979, we saw 14 patients with PAC in a small epidemic occurring in Iwakuni City, Japan. HBsAg was detected in sera from all patients. Subtyping of HBsAg in 11 patients showed that 8 had a determinant adr and 3 had no detectable determinant because of low antigen titers. The result suggests that factors other than the specific HBsAg subtype contribute to the development of PAC.</p