Increased length of a protein-coding CAG repeat within the androgen receptor gene appears to be the only type of mutation responsible for spino-bulbal muscular atrophy (SBMA or Kennedy disease). We have analysed a large 4-generation SBMA family and found that the mutant allele was unstable upon transmission from parent to child, with a documented variation from 46 to 53 repeats and a tendency to increase in size (7 increases and a single decrease in 17 events), which appeared stronger upon transmission from a male than from a female. Our results suggest also limited somatic instability of the abnormal allele, with observable variation of up to 2-3 repeats. This indicates that the behavior of the CAG repeat is similar to that observed for small premutations in the fragile X syndrome, or small abnormal alleles in myotonic dystrophy, two diseases which are caused by expansion of an unstable trinucleotide repeat.

In a four-generation family, chondrodysplasia punctata was found in a boy and one of his maternal uncles. These two patients also have short stature, as do all female members of the family, DNA molecular analysis of the pseudoautosomal and Xp22.3-specific loci revealed the presence of an interstitial deletion that cosegregates with the phenotypic abnormalities. The proximal breakpoint of this deletion was located distal to the DXS31 locus and the distal breakpoint in the pseudoautosomal region between DXYS59 and DXYS17. This maps the recessive X-linked form of chondrodysplasia punctata between the proximal boundary of the pseudoautosomal region and DXS31, and an Xp gene controlling growth between DXYS59 and DXS31.

A case of complex structural rearrangement of chromosome 4 identified by R-banding as 46,XX,del(4),inv(4)(pter leads to 16::q24 leads to p16::q32 leads to qter) is reported in an infant with congenital anomalies and psychomotor retardation.

The name Fryns syndrome was given to a new variable multiple congenital anomaly syndrome, almost always lethal, described in 1978, and now known to be autosomal recessive. Since that date, 20 patients have been reported in the literature. We describe 8 new cases, 6 of which were diagnosed in a series of 112276 consecutive births (livebirths and perinatal deaths). The prevalence of this syndrome can be estimated to be around 0.7 per 10000 births. These new cases confirm that the most frequent anomalies are diaphragmatic defects, lung hypoplasia, cleft lip and palate (often bilateral), cardiac defects (septal defects and aortic arch anomalies), renal cysts (type II, III or IV), urinary tract malformations, and distal limb hypoplasia. Most patients also have hypoplastic external genitalia and anomalies of internal genitalia (bifid or hypoplastic uterus, immature testes). The digestive tract is also often abnormal: duodenal atresia, pyloric hyperplasia, malrotation and common mesentery are present in half of the patients. When the brain was examined, more than half were abnormal (Dandy‐Walker anomaly and agenesis of corpus callosum). A few patients demonstrated cloudy cornea. We examined the eyes of three patients histologically: two of them showed retinal dysplasia with rosettes and gliosis of the retina, thickness of posterior capsula of lens and irregularities of the Bowman membrane. Four of our cases were diagnosed prenatally between 24 and 27 weeks. It is to be expected that prenatal diagnosis will be made often and earlier in the future, as the spectrum of anomalies of the Fryns syndrome can easily be evidenced by sonography.

A poorly developed female infant with buphthalmia, Turner phenotype, and mental retardation is described. Blood culture revealed a 45,X/47,XY,+18 chromosomal mosaicism; fibroblast culture showed only 45,X cells. The baby was dead at 11 months. Post mortem examination exhibited an ovarian agenesis and a calcified aortic stenosis.