A homozygous FKRP start codon mutation is associated with Walker-Warburg syndrome, the severe end of the clinical spectrum

• Published in: Clinical genetics 2010-09, Vol.78 (3), p.275-281
• Main Authors: Van Reeuwijk, J, Olderode-Berends, MJW, Van Den Elzen, C, Brouwer, OF, Roscioli, T, Van Pampus, MG, Scheffer, H, Brunner, HG, Van Bokhoven, H, Hol, FA
• Format: Article
• Language: English
• Subjects: Base Sequence; Biological and medical sciences; Brain; cobblestone lissencephaly; Codon, Initiator - genetics; Codons; DNA Mutational Analysis; dystroglycan; Embryos; Families & family life; Fatal Outcome; Female; fkrp; fukutin-related protein; Fundamental and applied biological sciences. Psychology; General aspects. Genetic counseling; Genetic disorders; Genetics of eukaryotes. Biological and molecular evolution; Genotype & phenotype; Glycosyltransferase; Homozygote; Humans; Infant, Newborn; Intelligence; Lethality; Male; Malformations of the nervous system; Medical genetics; Medical sciences; Molecular and cellular biology; Muscular dystrophy; Mutation; Neurology; O-linked glycosylation; Pampus; Pedigree; Proteins - genetics; Severity of Illness Index; Siblings; start codon mutation; Walker; Walker-Warburg Syndrome - genetics; Walker-Warburg Syndrome - pathology; Warburg syndrome
• ISSN: 0009-9163; 1399-0004
• DOI: 10.1111/j.1399-0004.2010.01384.x

van Reeuwijk J, Olderode‐Berends MJW, van den Elzen C, Brouwer OF, Roscioli T, van Pampus MG, Scheffer H, Brunner HG, van Bokhoven H, Hol FA. A homozygous FKRP start codon mutation is associated with Walker–Warburg syndrome, the severe end of the clinical spectrum. Dystroglycanopathies are a heterogeneous group of disorders caused by defects in the glycosylation pathway of α‐dystroglycan. The clinical spectrum ranges from severe congenital muscular dystrophy with structural brain and eye involvement to a relatively mild adult onset limb‐girdle muscular dystrophy without brain abnormalities and normal intelligence. Mutations have been identified in one of six putative or demonstrated glycosyltransferases. Many different FKRP mutations have been identified, which cover the complete clinical spectrum of dystroglycanopathies. In contrast to the other known genes involved in these disorders, genotype–phenotype correlations are not obvious for FKRP mutations. To date, no homozygous or compound heterozygous null mutations have been identified in FKRP, suggesting that null mutations in FKRP could result in embryonic lethality. We report a family with two siblings carrying a homozygous mutation in the start codon of FKRP that is likely to result in a loss of functional FKRP protein. The clinical phenotype of the patients was consistent with Walker–Warburg syndrome, the most severe disorder in the disease spectrum of dystroglycanopathies.