Homozygosity mapping in families with Joubert syndrome identifies a locus on chromosome 9q34.3 and evidence for genetic heterogeneity

Kathrin Saar, Lihadh Al-Gazali, László Sztriha, Franz Rueschendorf, Mohammed Nur-E-Kamal, André Reis, Riad Bayoumi

Research output: Contribution to journalArticlepeer-review

129 Citations (Scopus)

Abstract

Joubert syndrome is a rare developmental defect of the cerebellar vermis, with autosomal recessive inheritance. The phenotype is highly variable and may include episodic hyperpnea, abnormal eye movements, hypotonia, ataxia, developmental delay, and mental retardation. Even within sibships the phenotype may vary, making it difficult to establish the exact clinical diagnostic boundaries of Joubert syndrome. To genetically localize the gene region, we have performed a whole-genome scan in two consanguineous families of Arabian/Iranian origins, with multiple affected probands. In one family, we detected linkage to the telomeric region of chromosome 9q, close to the marker D9S158, with a multipoint LOD score of Z = +3.7. The second family did not show linkage to this region, giving a first indication of genetic heterogeneity underlying Joubert syndrome. These findings were supported by subsequent analysis of two smaller families - one compatible with linkage to 9q; the other, unlinked. We conclude that Joubert syndrome is clinically and genetically heterogeneous and that one locus maps to chromosome 9q.

Original languageEnglish
Pages (from-to)1666-1671
Number of pages6
JournalAmerican Journal of Human Genetics
Volume65
Issue number6
DOIs
Publication statusPublished - 1999

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

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