A novel TSC2 mutation in a Chinese family with tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a multisystem disorder characterized by widespread hamartomas in several organs, which is genetically subdivided into two types: TSC1 (MIM 191100) and TSC2 (MIM 613254) (Orlova and Crino 2010). The affected genes are TSC1 and TSC2, encoding hamartin and tuberin, respectively (Curatolo et al. 2008). The clinical features of TSC depend on which organ the hamartomas originate, including seizures, mental retardation, facial angiofibroma, renal angiomyolipoma and cardiac rhabdomyoma, etc. Age of onset is usually 0–15 years (Franz et al. 2010). Population-based studies in the West reported an incidence rate of TSC about one in 6000 to one in 10000 live births (Morrison 2009). TSC1, located in 9q34.13, contain 23 exons and encompasses 55 kb of DNA. TSC2, located in 16p13.3, contain 41 exons and encompasses 40 kb of DNA (van Slegtenhorst et al. 1997; van Bakel et al. 1997). Over 900 mutations have been found in the two genes (http://www.hgmd.cf.ac.uk/ac). Recent studies in the TSC patients indicated that mutations of TSC2 were higher than that of TSC1 (Sancak et al. 2005; van Eeghen et al. 2012). However, there were no mutation hotspots in the two genes. So, more novel mutations should be identified to enhance our insight into the molecular basis for the pathogenesis of TSC. In this report, we characterized a Chinese family with TSC based on the medical history, clinical manifestations and auxiliary examinations. A mutation screening of the TSC1/TSC2 gene was carried out and a novel deletion mutation (c.2690delT) in the TSC2 gene was identified. Here, we describe the results of the mutation analysis as well as clinical features related to the patients in this family.