title: Mutational analysis of SDCCAG8 in Bardet-Biedl syndrome patients with renal involvement and absent polydactyly.
abstract: OBJECTIVE
  To assess for SDCCAG8 mutations in Bardet-Biedl syndrome (BBS) subjects with renal involvement and no polydactyly, and to describe phenotypic characteristics of SDCCAG8-related disease.
  
  
  METHODS
  Five patients (from 4 pedigrees) with clinical diagnosis of BBS, who had retinal and renal involvement and no polydactyly, were assessed. Sequence analysis of SDCCAG8 was undertaken and a detailed clinical review of an affected sibship was performed.
  
  
  RESULTS
  A sibship of East Indian origin who carried a putative clinical diagnosis of BBS had compound heterozygous mutations in SDCCAG8 (p.Thr482LysfsX12/p.Asp543AlafsX24). The renal involvement was early and required transplant in both cases. Both were short statured and had asthma since childhood. The younger sister also had non-alcoholic fatty liver disease. Visual acuity and central fields were preserved in the teenage years in both patients. The optical coherence tomography showed preservation of the retinal lamination at the fovea; fundus autofluorescence demonstrated a perifoveal ring of hyperfluorescence as commonly observed in other forms of retinitis pigmentosa. Full-field electroretinogram revealed rod function to be more severely affected than cone function in both cases.
  
  
  CONCLUSIONS
  Our results and prior literature suggest that SDCCAG8 could play an important role in presumed BBS patients affected with severe kidney disease and absent polydactyly. This report enhances the phenotypic description of SDCCAG8-related disease.
authors.affiliation: Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Gail
authors.initials: G
authors.lastname: Billingsley
authors.forename: Ajoy
authors.initials: A
authors.lastname: Vincent
authors.forename: Catherine
authors.initials: C
authors.lastname: Deveault
authors.forename: Elise
authors.initials: E
authors.lastname: Héon
mesh_terms: D000293:Adolescent; D000328:Adult; D001324:Autoantigens / Q000235:genetics*; D020788:Bardet-Biedl Syndrome / Q000175:diagnosis / Q000235:genetics*; D002648:Child; D004252:DNA Mutational Analysis; D004596:Electroretinography; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D007674:Kidney Diseases / Q000235:genetics* / Q000601:surgery; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics*; D010375:Pedigree; D010641:Phenotype; D017689:Polydactyly / Q000235:genetics*; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology
chemical_list: D001324:Autoantigens; D009363:Neoplasm Proteins; C472380:SDCCAG8 protein, human