Association between altered placental human chorionic gonadotrophin (hCG) production and the occurrence of cryptorchidism: a retrospective study.

Background: An increase in cryptorchidism has been reported in many countries. One mechanism could be low fetal testosterone production possibly secondary to altered placental human chorionic gonadotrophin (hCG) release. Our Objective was to compare hCG values from maternal blood between boys with cryptorchidism and normal boys.

Novel molecular diagnostic approaches for X-linked centronuclear (myotubular) myopathy reveal intronic mutations.

X-linked centronuclear myopathy (XLMTM), also called myotubular myopathy, is a severe congenital myopathy characterized by generalized hypotonia and weakness at birth and the typical histological finding of centralization of myo-nuclei. It is caused by mutations in the MTM1 gene encoding the 3-phosphoinositides phosphatase myotubularin. Mutations in dynamin 2 and amphiphysin 2 genes lead to autosomal forms of centronuclear myopathy (CNM).

Mucopolysaccharidosis type IIID: 12 new patients and 15 novel mutations.

Mucopolysaccharidosis III D (Sanfilippo disease type D, MPS IIID) is a rare autosomal recessive lysosomal storage disorder previously described in only 20 patients. MPS IIID is caused by a deficiency of N-acetylglucosamine-6-sulphate sulphatase (GNS), one of the enzymes required for the degradation of heparan sulphate. So far only seven mutations in the GNS gene have been reported.

Very low alpha-fetoprotein in Down syndrome maternal serum screening.

Objective: To establish the frequency of very low maternal serum AFP and to differentiate congenital AFP deficiency from those diseases known to be associated with low AFP.

Methods: AFP values below 2 microg/L and borderline values up to 3 microg/L were retrospectively analysed in 839 773 singleton pregnancies included in a programme for routine screening of trisomy 21 maternal serum markers.

Results: Serum AFP was undetectable (< or =2 microg/L) in 8 cases, giving a frequency of 1/105 000.

Molecular analysis of 53 fragile X families with the probe StB12.3.

Fifty-three pedigrees with the fragile X syndrome have been studied for amplification of the CGG repeat sequence adjacent to the CpG island in the FMR1 gene. Probe StB12.3 allowed direct detection of affected males, carrier females, normal transmitting males, as well as prenatal diagnosis.

[Direct diagnosis of predominant mutation delta F508 associated with the mucoviscidosis gene].

The cystic fibrosis locus was mapped on the long arm of the chromosome 7 in 1985. It has recently been cloned and a three base pair deletion has been recognized as the mutation associated with the majority of CF chromosomes (delta F508). CF haplotypes previously defined with tightly associated DNA markers were analysed using PCR (Polymerase Chain Reaction) and allele specific oligonucleotides to determine the presence or absence of this mutation.

Multibranched chromosomes in the ICF syndrome: immunodeficiency, centromeric instability, and facial anomalies.

A new patient with the rare ICF syndrome (immunodeficiency, centromeric heterochromatin instability, and facial anomalies) is reported. The six patients previously reported in the literature are reviewed. The main clinical and cytogenetic characteristics of the syndrome are discussed.

Molecular analysis of a reciprocal translocation t(5;11) (q11;p13) in a WAGR patient.

Most patients with the complex association aniridia - predisposition to Wilms' tumor (WAGR syndrome) present with a de novo constitutional deletion of band 11p13. We report a patient with WAGR syndrome and a reciprocal translocation between chromosomes 5 and 11 t(5;11) (q11;p13). High resolution banding cytogenetic analysis and molecular characterization using 11p13 DNA markers showed a tiny deletion encompassing the gene for CAT but sparing the gene for FSHB.

Linkage analysis suggests at least two loci for X-linked non-specific mental retardation.

Epidemiological studies have suggested that non-specific X-linked mental retardation (XLMR) might be at least as frequent as the fragile X syndrome. The identification of all mutations causing XLMR would thus appear of prime importance. In the absence of other clinical signs the problem of genetic heterogeneity is acute.

[What course should be adopted after the discovery of a gonosome anomaly in the fetal karyotype?].

An experience of three centers of genetic counselling (West France). The authors attempts to explain why in 9 cases the pregnancy was not terminated.

Evidence for the presence of beta-subunit of hexosaminidase in a case of Sandhoff disease using a blotting technique.

Hexosaminidases, lysosomal enzymes whose deficiency is responsible for several genetic disorders, exist as two major forms: form A, containing two types of subunits alpha and beta; and form B, containing only beta subunits. We have used a technique involving successively electrophoresis of denatured proteins, transfer (blotting) onto nitrocellulose, and labelling by appropriate antibodies raised against the dissociated forms of hexosaminidases A and B. This technique allows the detection of alpha and beta subunits in crude extracts of normal tissues.

Reactivating factors of human alpha-mannosidase mutant.

In a previous study, we compared the alpha-mannosidase from mannosidosis tissues to that from normal one and we characterized the mutant. In this work, we show that the mutant inactivation by dialysis is reversible in different conditions and we investigate the nature of mannosidosis reactivating factors. The results obtained on pathological tissue by dialysis and by addition of dialysis fluid (DF), pronase treated DF, amino acid mixture, bivalent ions: Ca++, Zn++, Mg++, Co++ DF containing EDTA or DF heated to 600 degrees C suggest the reactivating factor includes both peptides and ions.