title: The NPHP1 gene deletion associated with juvenile nephronophthisis is present in a subset of individuals with Joubert syndrome.
abstract: Joubert syndrome (JS) is an autosomal recessive multisystem disease characterized by cerebellar vermis hypoplasia with prominent superior cerebellar peduncles (the "molar tooth sign" [MTS] on axial magnetic resonance imaging), mental retardation, hypotonia, irregular breathing pattern, and eye-movement abnormalities. Some individuals with JS have retinal dystrophy and/or progressive renal failure characterized by nephronophthisis (NPHP). Thus far, no mutations in the known NPHP genes, particularly the homozygous deletion of NPHP1 at 2q13, have been identified in subjects with JS. A cohort of 25 subjects with JS and either renal and/or retinal complications and 2 subjects with only juvenile NPHP were screened for mutations in the NPHP1 gene by standard methods. Two siblings affected with a mild form of JS were found to have a homozygous deletion of the NPHP1 gene identical, by mapping, to that in subjects with NPHP alone. A control subject with NPHP and with a homozygous NPHP1 deletion was also identified, retrospectively, as having a mild MTS and borderline intelligence. The NPHP1 deletion represents the first molecular defect associated with JS in a subset of mildly affected subjects. Cerebellar malformations consistent with the MTS may be relatively common in patients with juvenile NPHP without classic symptoms of JS.
authors.affiliation: Division of Genetics and Developmental Medicine, Department of Pediatrics, University of Washington, Seattle, 98195, USA. mparisi@u.washington.edu
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Parisi
authors.forename: Craig L
authors.initials: CL
authors.lastname: Bennett
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Eckert
authors.forename: William B
authors.initials: WB
authors.lastname: Dobyns
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Gleeson
authors.forename: Dennis W W
authors.initials: DW
authors.lastname: Shaw
authors.forename: Ruth
authors.initials: R
authors.lastname: McDonald
authors.forename: Allison
authors.initials: A
authors.lastname: Eddy
authors.forename: Phillip F
authors.initials: PF
authors.lastname: Chance
authors.forename: Ian A
authors.initials: IA
authors.lastname: Glass
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000293:Adolescent; D002531:Cerebellum / Q000002:abnormalities* / Q000473:pathology; D002648:Child; D015331:Cohort Studies; D003241:Consanguinity; D003598:Cytoskeletal Proteins; D005260:Female; D006720:Homozygote; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000151:congenital* / Q000235:genetics* / Q000473:pathology; D008297:Male; D008565:Membrane Proteins; D018895:Microsatellite Repeats; D010375:Pedigree; D011506:Proteins / Q000235:genetics*; D017384:Sequence Deletion / Q000235:genetics*; D013577:Syndrome; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; C108725:NPHP1 protein, human; D011506:Proteins