A 5' splice region G-->C mutation in exon 3 of the human beta-spectrin gene leads to decreased levels of beta-spectrin mRNA and is responsible for dominant hereditary spherocytosis (spectrin Guemene-Penfao).

We studied a family with autosomal dominant hereditary spherocytosis (HS) associated with a mild spectrin deficiency. Linkage analysis using two microsatellite markers (D14S63 and D14S271) very close to the beta-spectrin gene (SPTB) showed that HS co-segregated with alleles of these microsatellite markers and the linkage between the marker and HS was statistically significant. The presence of a beta-spectrin protein polymorphism (beta-spectrin Vay; A1880V) in trans of the HS allele was not itself deleterious, but allowed the detection of decreased membrane expression of the spherocytic beta-spectrin allele in two HS-affected subjects. Direct sequencing of the coding exons of the beta-spectrin gene in one affected subject showed the presence of a G-->C transversion at the terminal nucleotide of exon 3, which did not change the leucine codon 100 (CTG-->CTC). The presence of the mutation was confirmed by restriction enzyme digestion at the DNA level in all affected SH members of the family. The G-->C mutation severely reduced the utilization of the 5' splice site and resulted in aberrant mRNA splicing with intron 3 retention.

Search for the candidate genes in dominant hereditary spherocytosis using linkage analysis.

Hereditary spherocytosis (HS) is an inherited hemolytic anemia characterized by the presence of dense spherocytic red cells. In HS patients, red cell membrane protein gel electrophoresis has identified different subsets of abnormalities: isolated spectrin deficiency, combined spectrin and ankyrin deficiency, band 3 deficiency. To direct the search for the molecular defect in 9 families with dominant HS, we developed microsatellite markers specific for the membrane protein encoding genes possibly involved in HS (alpha- and beta-spectrin, ankyrin and band 3 genes) and genotyped each family. In 5 families with isolated spectrin deficiency, the beta-spectrin gene was designated as candidate. In one family with combined spectrin/ankyrin deficiency, only the ankyrin gene was not excluded, whereas in the 3 HS families with band 3 deficiency, only the band 3 gene was not excluded. This work allowed development of a reliable methodology to search for candidate genes in HS and showed the frequent involvement of the beta-spectrin gene in HS with isolated spectrin deficiency.

[Septic erosion of the internal carotid artery and retrostylian phlegmon. Apropos of a case]. / Erosion septique de l'artère carotide interne et phlégmon rétro-stylien. A propos d'un cas.

The vascular complications of peritonsillar phlegmons have become exceptional. On the basis of a recent case, the authors sum up the criteria of severity, including: white puncture sample, paralysis of the 9th, 10th, 11th, 12th cranial nerves and of the cervical sympathetic nerve. Computed tomography allows not only refining the topographic diagnosis, but even sometimes diagnosing a pseudoaneurysm before it is fissured. At this stage, intraoperative radiology may probably prevent the unavoidable secondary rupture. If it cannot be used, preventive ligation must be proposed. In the absence of cataclysmic hemorrhage, this easier procedure usually does not cause any irreversible neurological deficit. If performed in emergency, it may entail a major risk, not only a neurological risk, but a vital risk as well.