title: Spectrum of ALMS1 variants and evaluation of genotype-phenotype correlations in Alström syndrome.
abstract: Alström syndrome is a monogenic recessive disorder featuring an array of clinical manifestations, with systemic fibrosis and multiple organ involvement, including retinal degeneration, hearing loss, childhood obesity, diabetes mellitus, dilated cardiomyopathy (DCM), urological dysfunction, and pulmonary, hepatic, and renal failure. We evaluated a large cohort of patients with Alström syndrome for mutations in the ALMS1 gene. In total, 79 disease-causing variants were identified, of which 55 are novel mutations. The variants are primarily clustered in exons 8, 10, and 16, although we also identified novel mutations in exons 12 and 18. Most alleles were identified only once (45/79), but several were found recurrently. Founder effects are likely in families of English and Turkish descent. We also identified 66 SNPs and assessed the functional significance of these variants based on the conserved identity of the protein and the severity of the resulting amino acid substitution. A genotype-phenotype association study examining 18 phenotypic parameters in a subset of 58 patients found suggestive associations between disease-causing variants in exon 16 and the onset of retinal degeneration before the age of 1 year (P = 0.02), the occurrence of urological dysfunction (P = 0.02), of DCM (P = 0.03), and of diabetes (P = 0.03). A significant association was found between alterations in exon 8 and absent, mild, or delayed renal disease (P = 0.0007). This data may have implications for the understanding of the molecular mechanisms of ALMS1 and provides the basis for further investigation of how alternative splicing of ALMS1 contributes to the severity of the disease.
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine 04609, USA.
authors.forename: Jan D
authors.initials: JD
authors.lastname: Marshall
authors.forename: Elizabeth G
authors.initials: EG
authors.lastname: Hinman
authors.forename: Gayle B
authors.initials: GB
authors.lastname: Collin
authors.forename: Sebastian
authors.initials: S
authors.lastname: Beck
authors.forename: Rita
authors.initials: R
authors.lastname: Cerqueira
authors.forename: Pietro
authors.initials: P
authors.lastname: Maffei
authors.forename: Gabriella
authors.initials: G
authors.lastname: Milan
authors.forename: Weidong
authors.initials: W
authors.lastname: Zhang
authors.forename: David I
authors.initials: DI
authors.lastname: Wilson
authors.forename: Tom
authors.initials: T
authors.lastname: Hearn
authors.forename: Purificação
authors.initials: P
authors.lastname: Tavares
authors.forename: Roberto
authors.initials: R
authors.lastname: Vettor
authors.forename: Caterina
authors.initials: C
authors.lastname: Veronese
authors.forename: Mitchell
authors.initials: M
authors.lastname: Martin
authors.forename: W Venus
authors.initials: WV
authors.lastname: So
authors.forename: Patsy M
authors.initials: PM
authors.lastname: Nishina
authors.forename: Jürgen K
authors.initials: JK
authors.lastname: Naggert
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics*; D001483:Base Sequence; D015331:Cohort Studies; D017931:DNA Primers; D005091:Exons; D005260:Female; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008297:Male; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D013577:Syndrome
chemical_list: D017931:DNA Primers