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We report on a female fetus of 24 weeks whose clinical and radiological findings were compatible with boomerang dysplasia (BD). However, histopathology was unusual with a lateral fan shaped diaphyseal ossification. This has never been described either in typical atelosteogenesis I (AT-I) or in BD. The purpose of this report is to find out if this condition is a separate lethal bone dysplasia or another histological feature of the nosological group of AT-I and BD.

Congenital microcoria is an autosomal dominant disorder characterized by a pupil with a diameter <2 mm. It is thought to be due to a maldevelopment of the dilator pupillae muscle of the iris, and it is associated with juvenile-onset glaucoma. A total genome search for the location of the congenital microcoria gene was launched in a single large family. We found linkage between the disease and markers located on 13q31-q32 (Zmax = 9.79; theta = 0). Haplotype analysis narrowed the linked region to an interval <8 cM between markers D13S1239 proximally and D13S1280 distally.

The cystic fibrosis (CF) gene has been cloned and a major mutation identified (delta F508). This 3-bp deletion has been found in approximately 70% of CF chromosomes. We have used the strategy of denaturing gradient gel electrophoresis followed by direct sequencing of the polymerase chain reaction products, in order to detect other mutations in exons 10, 11 and 20 of the CF transmembrane conductance regulator gene. A new mutation, F1286-S, was found in exon 20. It involves a nucleotide change of T-->C at nucleotide 3989 and changes a phenylalanine into serine at position 1286 of the protein.

We report the study of five independent X-linked hydrocephalus (HSAS1) families with polymorphic DNA markers of the Xq28 region. A total of 58 individuals, including 7 living affected males and 22 obligate carriers, have been studied. Maximum lod score was 7.21 at theta = 2.40% for DXS52 (St14-1). A single recombination event was observed between this marker and the HSAS1 locus. Other markers studied were DXS296 (Z = 2.02 at theta = 2.5%), DXS304 (Z = 4.37 at theta = 7.8%), DXS74 (Z = 3.50 at theta = 0%), DXS15 (Z = 1.96 at theta = 5.7%), DXS134 (Z = 3.31 at theta = 0%), and F8C (Z = 5.79 at theta = 0%). These data confirm the localization of the HSAS1 gene to Xq28 and provide evidence for genetic homogeneity of this syndrome. In addition, examination of two obligate recombinant meioses along with multipoint linkage analysis supports the distal localization of the HSAS1 locus with respect to the DXS52 cluster. These observations are of potential interest for future studies aimed at HSAS1 gene characterization.

We performed mutation analysis and RFLP haplotype analysis of chromosomes associated with classical phenylketonuria (PKU) in contemporary French families. We also did genealogical reconstructions for seven obligate carriers in five contemporary French-Canadian families living in eastern Quebec, who carry the M1V mutation causing PKU. The M1V mutation, heretofore considered to be associated exclusively with French-Canadians, was found on 4 of 152 independent French chromosomes. The French and Quebec M1V mutations all occurred on RFLP haplotype 2. The contemporary mutant French chromosomes clustered in southern Brittany (Finistère Sud). Genealogical reconstructions of the Quebec families identified 53 shared ancestors and a center of diffusion in the Perche region in 17th century France. The two clusters in France, one historical and the other contemporary, are not incompatible, if one assumes the possibilities that settlers returned from Nouvelle France or moved from Perche to southern Brittany. The M1V mutation is serving as a useful marker for historical demography.

More than 80% of the first degree relatives of 106 patients with iron overload - 97 with idiopathic haemochromatosis (I.H.) and nine with haemosiderosis secondary to alcohol induced liver disease (A.H. - were examined. Physical examination and measurement of plasma iron level and UIBC were done in all subjects; relatives who presented with some anomaly were submitted to a desferrioxamine test and, if the latter showed a high urinary iron output, to a liver biopsy. While absent in relatives of A.H. patients, iron overload was present in 78 out of 499 relatives of I.H. patients: 29 major and 49 minor forms. The major forms involved the sibships almost exclusively. The genetic analysis showed much evidence in favour of a recessive or rather intermediate form of inheritance, with heterozygous developing minor forms. However, other modes of transmission, especially polygenic (probably oligogenic), cannot be totally excluded. Data from recent studies showing a strong correlation between I.H. and certain HLA antigens do not conflict with the above conclusions.

TAR syndrome is usually an autosomal recessive disease; we report a family where the father of the propositus presented malformations of the feet, and review the known cases involving several generations. The authors of these cases concluded that the TAR syndrome is probably genetically heterogeneous.

The results provided by the Fédération des Centres d'Etude et de Conservation du Sperme Humain (CECOS) are based on 15,283 requests for AID. They are analysed from the point of view of medical genetics. The genetic indications represent 0.77% of requests for AID and can be separated into four groups: dominant autosomal abnormalities in the man, previous children affected by autosomal recessive conditions, chromosomal abnormalities in the man, and a miscellaneous group. In 2,502 births, a total of 45 malformations was seen, including nine chromosomal abnormalities. The possibility of an early amniocentesis for prenatal diagnosis in every pregnancy after AID is discussed.