MECP2 mutant allele in a boy with Rett syndrome and his unaffected heterozygous mother

• Published in: Brain & development (Tokyo. 1979) Vol. 29; no. 1; pp. 47 - 50
• Main Authors: Dayer, Alexandre G., Bottani, Armand, Bouchardy, Isabelle, Fluss, Joel, Antonarakis, Stylianos E., Haenggeli, Charles-Antoine, Morris, Michael A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 2007
• Subjects: Adult; Child, Preschool; DNA Mutational Analysis; Female; Gene Deletion; Gene Frequency - genetics; Genetic Diseases, X-Linked - genetics; Genetic Predisposition to Disease - genetics; Genetic Testing; Heterozygote; Humans; Inheritance Patterns - genetics; Male; MECP2; Mental retardation; Methyl-CpG-Binding Protein 2 - genetics; Mothers; Mutation - genetics; Penetrance; Phenotype; Rett syndrome; Rett Syndrome - diagnosis; Rett Syndrome - genetics; X Chromosome Inactivation - genetics; X-linked disease; MECP2; X-linked disease; Mental retardation; Rett syndrome
• ISSN: 0387-7604; 1872-7131
• DOI: 10.1016/j.braindev.2006.06.001

Rett syndrome is a severe neurodevelopmental disorder affecting principally females and characterized by a normal postnatal development followed by stagnation and regression of acquired skills. We report a 4-year-old boy with a Rett syndrome phenotype and his unaffected mother both carrying a 44 bp truncating deletion mutation (c.1158del44 or p.388X) in the MECP2 gene. The presence of a skewed X inactivation in the mother provides a possible explanation for the absence of penetrance. The finding of a MECP2 mutation in an unaffected female complicates genetic counseling and further confirms that it is essential to look for mutations in the mothers of all patients with MECP2 mutations.