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Novel POMGnT1 mutations define broader phenotypic spectrum of muscle-eye-brain disease.
- Source :
-
Neurogenetics [Neurogenetics] 2007 Nov; Vol. 8 (4), pp. 279-88. Date of Electronic Publication: 2007 Sep 29. - Publication Year :
- 2007
-
Abstract
- Muscle-eye-brain disease (MEB, OMIM 253280) is an autosomal recessive disorder characterized by a distinct triad of congenital muscular dystrophy, structural eye abnormalities, and cobblestone lissencephaly. Clinically, MEB patients present with early onset muscular hypotonia, severely compromised motor development, and mental retardation. Magnetic resonance imaging reveals a lissencephaly type II with hypoplasia of the brainstem and cerebellum. MEB is associated with mutations in the gene for protein O-mannose beta-1,2-N-acetylglucosaminyltransferase (POMGnT1, OMIM 606822). In this paper, we report the clinical findings of nine MEB patients from eight families. Eight of the nine patients presented typical features of MEB. However, a broad phenotypic variability was observed, ranging from two patients with severe autistic features to another patient with an unusually mild phenotype, initially diagnosed as congenital muscular dystrophy. Furthermore, severe hydrocephalus was reported in two families during a previous pregnancy, emphasizing the phenotypic overlap with Walker-Warburg syndrome. In addition to three previously reported mutations, we identified six novel POMGnT1 mutations (one missense, five truncating) in the present patient cohort. Our data suggest mutational hotspots within the minimal catalytic domain at arginine residue 442 (exon 16) and in intron 17. It is interesting to note that all mutations analyzed so far result in a complete loss of enzyme activity. Therefore, we conclude that the type and position of the POMGnT1 mutations are not of predictive value for the clinical severity. This supports the notion that additional environmental and/or genetic factors may contribute to the observed broad spectrum of POMGnT1-associated phenotypes.
- Subjects :
- Adolescent
Animals
Base Sequence
Child
Child, Preschool
Cobblestone Lissencephaly pathology
DNA genetics
Dystroglycans metabolism
Female
Genes, Recessive
Genotype
Heterozygote
Homozygote
Humans
Infant
Male
Mice
Mice, Knockout
Muscular Dystrophies congenital
Muscular Dystrophies pathology
Mutation, Missense
N-Acetylglucosaminyltransferases chemistry
N-Acetylglucosaminyltransferases deficiency
Phenotype
Syndrome
Cobblestone Lissencephaly enzymology
Cobblestone Lissencephaly genetics
Eye Abnormalities enzymology
Eye Abnormalities genetics
Muscular Dystrophies enzymology
Muscular Dystrophies genetics
Mutation
N-Acetylglucosaminyltransferases genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1364-6745
- Volume :
- 8
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Neurogenetics
- Publication Type :
- Academic Journal
- Accession number :
- 17906881
- Full Text :
- https://doi.org/10.1007/s10048-007-0096-y