Macrocephalic mental retardation associated with a novel C-terminal MECP2 frameshift deletion.

<bold>Unlabelled: </bold>We report a novel C-terminal MECP2 frameshift deletion (1135_1142delCCCGTG CC) in a 19-year-old woman with mental retardation and epilepsy. Preservation of language capabilities, purposeful hand use and sufficient locomotion implied an atypical variant of Rett syndrome (OMIM 312750). Occipito-frontal head circumference was large at birth (36 cm; SDS 1.7) and increased until adulthood (58.5 cm; SDS 2.3).<bold>Conclusion: </bold>Our observation indicates that head size and head growth are of limited reliability in the diagnosis of MECP2-associated phenotypes. [ABSTRACT FROM AUTHOR]