Perhaps half of all patients with multiple abnormalities have known, recognized syndromes. The other half represent unknown entities that need to be further delineated. The significance of syndrome delineation cannot be overestimated. As an unknown syndrome becomes delineated, its phenotypic spectrum, its natural history, and its risk of recurrence become known, allowing for better patient care and family counseling.

The process of syndrome delineation is discussed in terms of unknown genesis syndromes of the provisionally-unique and recurrent-pattern types, and known-genesis syndromes of the pedigree, chromosomal biochemical-defect, and environmentally-induced types. Several special syndrome categories are defined, including the chance syndrome, variant additive syndrome, association syndrome, exceptional chromosomal syndrome, and exceptional monogenic syndrome. Finally, a population definition of a syndrome is developed.

This paper presents a historical view of the development of the concept of ectodermal dysplasia, analyses five current “definitions” of the group, and classifies 52-57 ectodermal dysplasias into subgroups on the basis of criteria developed by the Author.

A series of house-to-house surveys in Central Brazil revealed 32 cases of reduction deformities of the limbs (brachydactyly, synbrachydactyly, ectrodactyly, amely, adactyly, achiry, apody, etc.) among 58,761 births (0.54 per thousand, being 0.66 per thousand among Whites and 0.43 per thousand among Mulattoes and Negroes). No sibship was found with two or more equally affected singleton members. One case of concordance among twins is referred. There were no parity, inbreeding, race and sex effects. Both hands and both feet were also equally affected. Precocious mortality and twinning were significantly higher among affected individuals. The presence of cleft lip and palate in one of our index patients may also reflect an etiological relationship. Among the sibs, the total incidence of congenital malformations was similar to that generally accepted for general populations.

A new family with the A2 type brachydactily is described. It is the first one observed in Italy and the sixth of the world literature. Brachymesophalangy of index fingers and/or second toes is the typical osseous malformation which was present in 14 individuals from 4 generations. The defect is transmitted by an autosomal dominant gene with high penetrance and variable expressivity.

A twin study on the significance of genetic factors for the variation in peak height and peak weight velocity, as well as in age at menarche and the development of secondary sex characteristics, is presented. Evidence of a rather strong genetic regulation of the occurrence of puberty was obtained in the analysis. The maximal height or weight gain (in cm/year or kg/year) seems to be, at least in girls, less influenced by genetic factors than the age at which it appears.

A comparison of physical capacity, (measured by vital capacity, muscular strength and physical work capacity) in twin boys and controls failed to indicate significant differences. Intrapair correlations showed the MZ twins to be much more similar than the DZ twins in all the capacity measures. The correlations were lower, however, for both MZ and DZ twins for physical work capacity than for the other two capacity variables. When amount of physical exercise during leisure time is kept under control, the DZ twins tend to be more similar for physical work capacity or muscular strength, and the correlations tend to be of the same magnitude for MZ twins. Physical work capacity therefore appears, in this study, to be a more environmentally influenced variable than either vital capacity or muscular strength.

Multivariate analyses are used to study the structural patterns of ridge counts of fingers. There is a significant difference between the ridge counts of two hands, chiefly due to the first and fourth fingers. There is asymmetry in the covariance matrix of the ridge counts. The correlations between fingers are significant and the decrease in correlation with increasing distance between fingers is not significant.

In a 3¾ year old boy with mental and physical retardation, a chromosome analysis from lymphocyte cultures revealed a partial deletion of chromosome 1q following a pericentric inversion. The chromosomes of the parents were normal. The clinical picture of the patient included the following characteristics: prominent occiput, small chin, deep-seated and dysplastic ears, abnormal vortices of the hair, divided tip of the tongue, high palate, small finger and toe nails, inguinal hernia both sides, undescended but normal sized testes, hypotonic musculature and overextensible joints, retardation of ossification in the left hand by 6-12 months, slight osteoporosis, EQ~0.5.

A follow-up investigation of a family 14/18 translocation has shown the first affected child to be followed by a healthy boy and by a similarly affected girl.

The chromosomal analysis of a phenotypically normal, moderately oligospermic man is reported. He presented a triple mosaic complement with two autosomally unbalanced cell lines. The cytogenetic results are discussed, and the importance of such investigations in men attending infertility clinics emphasized.

The finger and palm prints of 20 male and 18 female Shompen of Great Nicobar were examined. The distribution of finger patterns and of palmar main line formulae showed significant sex differences. Main line index was higher on right than on left hands in both sexes. Axial triradius t was most frequently observed on both hands in the two sexes.

Hypertrichosis pinnae auris, Darwin's point and tubercle, and muscle Palmaris Longus have been examined in 425 adult subjects from two endogamous groups of Patiala, Hindu Khatris (230) and Baniyas (195). No significant differences between the two groups were found for any of the three traits.

An analysis of familial liability to infant mortality is presented. Heritability estimates for three periods of the demographic evolution of an isolated population (Isle-aux-Coudres, Quebec) are provided. Average heritability is on the order of 27%. This is interpreted as being partly due to sibs common environment and partly to dominance variance effects of genes. The real additive variance of the familial liability might well be nil.