title: Mutations in POMT1 are found in a minority of patients with Walker-Warburg syndrome.
abstract: Walker-Warburg syndrome (WWS) is an autosomal recessive disorder of infancy characterized by hydrocephalus, agyria, retinal dysplasia, congenital muscular dystrophy, and over migration of neurons through a disrupted pial surface resulting in leptomeningeal heterotopia. Although previous work identified mutations in the o-mannosyl transferase, POMT1, in 6 out of 30 WWS families [Beltran-Valero de Bernabe et al., 2002], the incidence of POMT1 mutations in WWS is not known. We sequenced the entire coding region of POMT1 in 30 consecutive, unselected patients with classic WWS. Two novel heterozygous mutations were found in two patients from non-consanguineous parents, whereas 28 other patients failed to show any POMT1 mutations. One patient was found to be heterozygous for a transition, g.1233T > A, which predicts p.Y352X. A second patient was found also to be heterozygous for a transition g.1790C > G, which predicts p.S537R. As an additional determination of the frequency of the POMT1 mutations in WWS, we tested for linkage of WWS to POMT1 in six consanguineous families. All six demonstrated heterozygosity and negative LOD scores at the POMT1 locus. From these data we show that POMT1 is an uncommon cause of WWS, the incidence of coding region mutations in this population of WWS being less than 7%. We conclude that while the incidence of POMT1 mutations in WWS can be as high as 20% as reported by Beltran-Valero de Bernabe et al. [2002] and it can be as low as approximately 7%, as reported here.
authors.affiliation: Howard Hughes Medical Institute and Department of Neurology Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
authors.forename: Sophie C
authors.initials: SC
authors.lastname: Currier
authors.forename: Christine K
authors.initials: CK
authors.lastname: Lee
authors.forename: Bernard S
authors.initials: BS
authors.lastname: Chang
authors.forename: Adria L
authors.initials: AL
authors.lastname: Bodell
authors.forename: G Shashidhar
authors.initials: GS
authors.lastname: Pai
authors.forename: Leela
authors.initials: L
authors.lastname: Job
authors.forename: Lieven G
authors.initials: LG
authors.lastname: Lagae
authors.forename: Lihadh I
authors.initials: LI
authors.lastname: Al-Gazali
authors.forename: Wafaa M
authors.initials: WM
authors.lastname: Eyaid
authors.forename: Greg
authors.initials: G
authors.lastname: Enns
authors.forename: William B
authors.initials: WB
authors.lastname: Dobyns
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Walsh
mesh_terms: D000015:Abnormalities, Multiple / Q000208:ethnology / Q000235:genetics* / Q000473:pathology; D001483:Base Sequence; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics; D003241:Consanguinity; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004252:DNA Mutational Analysis; D005124:Eye Abnormalities; D005260:Female; D008040:Genetic Linkage; D006801:Humans; D008126:Lod Score; D008297:Male; D008364:Mannosyltransferases / Q000235:genetics*; D018895:Microsatellite Repeats; D009136:Muscular Dystrophies / Q000473:pathology*; D009154:Mutation; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D013577:Syndrome
chemical_list: D004247:DNA; D008364:Mannosyltransferases; C082696:protein O-mannosyltransferase