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.

A case of Turner's syndrome was found to be 46,XXqi/47,XXqi Xp-, a new mosaic. The origin of such a mosaic, the formation of the Xq isochromosome using the C-banding technique, and the X chromosome inactivation are discussed. The Xq isochromosome was apparently monocentric, but probably with two strictly close centromeres. The inactivated X seemed to be the Xqi or the normal X alternatively.

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.

Six cases of trisomy 4p and three of trisomy 9p are reported. Growth retardation is an aspecific clinical sign, present in both of these “new autosomal” syndromes. Growth hormone determinations fit in the normal range. The attempts to subclassify these disorders correlating the severity of clinical manifestations and the size of the imbalanced chromosome segment, are considered unrealistic approaches.

The preliminary results of a cytogenetic analysis of blast index, mitotic index and association index, as well as of morphological indices of chromosomes 1, 9 and 16, carried out on two subsamples of twin pairs of different age groups, seem to indicate that the genetic material may undergo some process of transformation with time.

We described a D1 trisomy syndrome patient who had a normal 46,XX cell line and 15.4% of lymphocytes with a 47,XX,+D chromosome constitution as an occasion to review normal trisomy 13 mosaicism.

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.

In three girls, aged 14, 15 and 16 years, the chromosome analysis revealed a morphologically abnormal, enlarged X-chromosome resembling in size and centromere position the chromosome no. 2. The translocation points were different in all three cases. The Barr-bodies were enlarged. In two girls a 45,X mosaicism (25% and 10%) was found in lymphocyte cultures.

The length at birth was 43, 47 and 48 cm, and none of the girls was born before term. The main clinical abnormalities in all three cases were a marked growth retardation, slight morphological dysplasias, lack of sexual development and social immaturity. GH and Cortisol secretion during an insulin tolerance test were normal. LH and FSH were elevated and showed an exaggerated reaction on LH-RH. Oestrogens were low normal and androgens within the normal range. At laparatomy the gonads were found to be streak gonads. For two girls cell cultures of gonadal tissue were set up? the chromosome findings of which corresponded to those of the lymphocyte cultures.

The abnormality of the gonosomes reported here seems to represent a special form of gonadal dysgenesis. Although the translocation points were different in the three patients and one had no mosaic, while the other two showed 45,X/46,XX mosaicism, the clinical and hormonal findings were nearly the same for all three girls.

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.

A definition of efficiency is presented to aid a researcher in the choice of the genetic systems for the diagnosis of twin zygosity. An expression is given that produces a numeric value that indicates which systems do the most effective job of discriminating DZ twins from a sample of twin pairs. This definition of efficiency is illustrated with eight blood groups commonly used in twin zygosity diagnosis.

It is shown that the within twin-pair difference is the most important source of information in determination of twin zygosity using dermatoglyphic data. Inclusion of a measure of among-pair variability provides added discrimination beyond that found with the within-pair difference alone.

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.

A case of a patient carrying a 9p trisomy due to a maternal t(9;18) (p 13;p11) translocation is reported. In addition to the principal findings which characterize the 9p trisomy syndrome, this case presents some dysmorphic features due to the partial deletion of chromosome 18.

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.

A computer system for simulation of quantitative twin data is being developed. The capability is being built in to simulate distributions with known means, standard deviations, skewness and kurtosis.

Two unrelated patients with multiple congenital malformations and severe mental retardation were found to be carrier of a non-mosaic ring 22 chromosome abnormality. These observations further confirm the phenotypical variability of r(22) expression, which makes unreliable the attempts to delineate a clinical profile of the syndrome

In four families of color blind subjects, a dermatoglyphic analysis was made and the results compared with data from normal subjects. The Student's t test, howeverf failed to show any significant differences in the means of the two groups.

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.

Detailed comparison of human variant chromosomes found by Q- and C-banding technique is performed in a pair of twins to show that these variants can be used for zygosity diagnosis.