title: Recessive Schwartz-Jampel syndrome (SJS): confirmation of linkage to chromosome 1p, evidence of genetic homogeneity and reduction of the SJS locus to a 3-cM interval.
abstract: Schwartz-Jampel syndrome (SJS), or chondrodystrophic myotonia, is a rare autosomal recessive disorder characterized by generalized myotonia resulting in a particular, recognizable facies and osteoarticular abnormalities. Some of us have recently shown genetic linkage of SJS to a locus on 1p34-p36.1 in five families. Here, we show by homozygosity mapping and segregation analysis that eight new families are most likely linked to the SJS locus on chromosome 1, confirming the localization of SJS to chromosome 1p and suggesting genetic homogeneity. Recombination events reduced the SJS locus from a genetic interval of 8 to 3 cM, which should facilitate the identification of the SJS gene. Low clinical variability was observed between the studied families, except for osteoarticular abnormalities. Since the severity and the location of osteoarticular abnormalities varied from one individual to another, even in the same families, other factors than the SJS gene itself, genetic or epigenetic, might contribute to the phenotype.
authors.affiliation: Fédération de Neurologie and INSERM U134, Hôpital de la Salpètrière, Paris, France.
authors.forename: B
authors.initials: B
authors.lastname: Fontaine
authors.forename: S
authors.initials: S
authors.lastname: Nicole
authors.forename: H
authors.initials: H
authors.lastname: Topaloglu
authors.forename: C
authors.initials: C
authors.lastname: Ben Hamida
authors.forename: P
authors.initials: P
authors.lastname: Beighton
authors.forename: F
authors.initials: F
authors.lastname: Spaans
authors.forename: J M
authors.initials: JM
authors.lastname: Cantu
authors.forename: S
authors.initials: S
authors.lastname: Bakouri
authors.forename: N
authors.initials: N
authors.lastname: Romero
authors.forename: K
authors.initials: K
authors.lastname: Ricker
authors.forename: P
authors.initials: P
authors.lastname: Barros-Nunez
authors.forename: G
authors.initials: G
authors.lastname: Ponsot
authors.forename: M
authors.initials: M
authors.lastname: Ben Hamida
authors.forename: J
authors.initials: J
authors.lastname: Weissenbach
authors.forename: F
authors.initials: F
authors.lastname: Hentati
authors.forename: F
authors.initials: F
authors.lastname: Lehmann-Horn
mesh_terms: D000483:Alleles; D001483:Base Sequence; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1; D017931:DNA Primers; D005260:Female; D005808:Genes, Recessive; D008040:Genetic Linkage; D005819:Genetic Markers; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010009:Osteochondrodysplasias / Q000235:genetics*; D010375:Pedigree
chemical_list: D017931:DNA Primers; D005819:Genetic Markers