Clinico-pathogenetic findings and management of chondrodystrophic myotonia (Schwartz-Jampel syndrome): a case report.

Background: Chondrodystrophic myotonia or Schwartz-Jampel syndrome is a rare genetic disorder characterized by myotonia and skeletal dysplasia. It may be progressive in nature. Recently, the gene responsible for Schwartz-Jampel syndrome has been found and the defective protein it encodes leads to abnormal cartilage development and anomalous neuromuscular activity.

Gaucher disease and parkinsonism: a phenotypic and genotypic characterization.

Among the many phenotypes associated with Gaucher disease, the inherited deficiency of glucocerebrosidase, are reports of patients with parkinsonian symptoms. The basis for this association is unknown, but could be due to alterations in the gene or gene region. The human glucocerebrosidase gene, located on chromosome 1q21, has a nearby pseudogene that shares 96% identity.

Glucocerebrosidase mutations among African-American patients with type 1 Gaucher disease.

While the inherited deficiency of the enzyme glucocerebrosidase (Gaucher disease) is panethnic in its distribution, there have not been studies of the mutations encountered in specific ethnic groups in the United States, other than those on Ashkenazi Jews. We present the clinical descriptions and genotypes of seven patients of African-American ancestry with type 1 Gaucher disease, and summarize the published literature regarding the genotypes encountered in this population. All seven of the patients had moderate-to-severe manifestations of the disease, and all developed symptoms by adolescence.

Gene rearranagement on 1q21 introducing a duplication of the glucocerebrosidase pseudogene and a metaxin fusion gene.

The genes for glucocerebrosidase and metaxin, both located on chromosome 1q21, each have a highly homologous pseudogene sequence nearby. We describe a novel recombinant allele consisting of a duplication of the glucocerebrosidase pseudogene and a fusion between the metaxin gene and its pseudogene, resulting from a crossover between metaxin and pseudometaxin in the region downstream of the glucocerebrosidase gene. We also show that certain individuals have a metaxin-pseudometaxin fusion gene without a duplication, resulting from the same crossover.

Glucocerebrosidase gene mutations in patients with type 2 Gaucher disease.

Gaucher disease, the most common lysosomal storage disorder, results from the inherited deficiency of the enzyme glucocerebrosidase. Three clinical types are recognized: type 1, non-neuronopathic; type 2, acute neuronopathic; and type 3, subacute neuronopathic. Type 2 Gaucher disease, the rarest type, is progressive and fatal.