Lymphoblasts from SCA11 patients (c.1329insA; c.1284_1285delAG) presented mRNA levels reduced by approximately 50%, when compared to unaffected individuals, suggesting that mutated mRNA is prematurely degraded by nonsense-mediated decay (NMD), causing TTBK2 haploinsufficiency. This evidence concerns the gene TTBK2 and spinocerebellar ataxia type 11.