Mild Phenotype in Tuberous Sclerosis Patients with a Codon 905 Missense Mutation in the TSC2 Gene

Autor: Andermann, E, Jansen, Anna, Sancak, Ozgur, D'agostino, Md, Badhwar, Amanpreet, Roberts, P., Wilkinson, R., Melanson, Denis, Tampieri, Donatella, Maat-Kievit, Anneke, Goedbloed, Myriam, Van Den Ouweland, A.m., Nellist, Mark, Pandolfo, M., Sims, K., Thiele, Elizabeth, Dubeau, François, Andermann, Frederick, Kwiatkowski, David, Halley, D.
Přispěvatelé: Public Health Care, Public Health Sciences, Mental Health and Wellbeing research group
Jazyk: angličtina
Rok vydání: 2006
Předmět:
Popis: Purpose: Tuberous sclerosis complex is an autosomal dominant disorder characterised by hamartomatous growth in various organs, and caused by mutations in the TSC1 (9q34) or TSC2 (16p13) genes. Overall, TSC2 mutations have been associated with a more severe disease phenotype than TSC1 mutations. We report the clinical and molecular features in16 families with TSC2 mutations and mild phenotypes. Method: We carried out a detailed study of the TSC phenotype and genotype in a large French-Canadian kindred (Family A). In addition, clinical and molecular data on 15 families with mutations at the same codon were collected. Functional studies were performed on three different missense mutations and related to the phenotypes. Results: A 2714G > A (R905Q) missense mutation in exon 23 of TSC2 was identified in 25 individuals in Family A. The TSC phenotype in this family was unusually mild, characterised mainly by depigmented skin lesions and by seizures that remitted spontaneously or that wereeasily controlled with antiepileptic drugs. Diagnostic criteria were met in only a minority of family members, delaying diagnosis. All other families with the R905Q mutation were found to have a similar mild phenotype. Patients with a 2713C > T (R905W) mutation or a 2713C > G (R905G) mutation had a more severe phenotype. In 3 different assays, the R905W and R905G substitutions had a more severe effect on tuberin function than the R905Q substitution. Conclusion: We identified 16 families with codon 905 missense changes in TSC2. In the R905Q families, the TSC phenotype was unusually mild, consistent with the functional studies. Our findings support the observation that familial TSC is less severe than sporadic TSC, even when it is due to a TSC2 mutation. Genotype-phenotype correlations indicate that mild TSC phenotypes may be associated with specific TSC2 mutations.
Databáze: OpenAIRE