A new form of congenital muscular dystrophy with joint hyperlaxity maps to 3p23-21.

Congenital muscular dystrophies (CMDS) are a heterogeneous group of disorders. A growing number of CMDS have been found to be associated with joint hyperlaxity. We recruited 14 French-Canadian cases belonging to 11 families affected by a novel autosomal recessive congenital muscular dystrophy with hyperlaxity (CMDH). All cases come from the southwestern part of Quebec, suggesting a new French-Canadian founder effect. All patients present muscle weakness, proximal contractures coexisting with distal joint hyperlaxity. Pathological and genetic studies have excluded that mutations in the three genes coding for collagen VI subunits are responsible for this disease. A genome-wide scan established linkage of two CMDH families to a region on chromosome 3p23-21. Further linkage analysis confirmed that all families are linked to the same region (log of the odds score of 5.3). Haplotype analysis defines a 1.6-cM candidate interval and suggests that two common mutations may account for 78% of carrier chromosomes. This study describes and maps a new form of recessive CMD with joint hyperlaxity distinct from Ullrich and Bethlem myopathies with a founder effect in the French-Canadian population.

Primary thrombocythemia in pregnancy: a report of two cases.

We report two cases of primary thrombocythemia diagnosed during pregnancy. One patient developed transient visual field defects. She was treated with plateletpheresis at term and delivered of a normal child by cesarean section. The second patient was not treated. Intrauterine fetal death occurred at 36 weeks' gestation from multiple placental infarcts. In cases of primary thrombocythemia, we suggest close monitoring of both mother and fetus throughout pregnancy.