com) (Fig. 2). In addition to the highly conserved exonic regions, two intronic regions (introns 2 and 7) of the WASP were found to have apparent high

evolutionary conservation. PCR-sequencing, however, did not detect any variants. We previously described the termination codon mutation in the WASP gene in a Thai family affected with classic WAS [13]. This study further reported the clinical manifestations and long-term follow-up of seven unrelated patients with molecular diagnosis of classic WAS. In addition to the previously reported mutation, four different recurrent mutations were identified, including two missense mutations, an insertion and a 4-bp deletion in intron 8. One novel nonsense (c.55C > T, p.Q19X) IWR-1 chemical structure mutation was also detected. No causative mutations in the coding, promoter and conserved intronic regions could be identified in case 2. The patient had classic Apoptosis inhibitor WAS with a score of 4, and no WASP expression could be detected in his cells by immunoblot analysis (courtesy of Dr. Hubert B. Gaspar and Dr. Kimberly C. Gilmour, UK). It remains possible that the mutation could be located in the noncoding parts of the gene including regulatory regions. Our patients with classic WAS

had the age of onset ranging from 6 days to 8 months. Of these seven cases, two developed AIHA, which included the previously reported patient (case 1) with the c.1507T > A (p.X503R) mutation (Table 1). As there are no available HLA-matched donors, this patient has been given monthly IVIG and sulfamethoxazole-trimethoprim prophylaxis. learn more The missense mutations (p.R86N) at position 86, one of the common hot spot mutations found in the WASP gene, were identified in two unrelated patients. One with a WAS score of 4 carried

the c.256C > T (p.R86C) mutation. The other with a WAS score of 5 harboured the c.257G > A (p.R86H) mutation. The missense mutations at position 86 (p.R86N) have been found to be commonly associated with the XLT phenotype. However, some patients with these particular mutations can have a more severe phenotype with a score of 3–5 [10, 12, 17]. The previously reported c.1272insG (p.G424GfsX494) and IVS8 + 3 to 6del GAGT mutations in patients with classic WAS were also detected in the Thai population. The novel nonsense (c.55C > T, p.Q19X) mutation expected to result in the formation of a truncated protein lacking most of the functional domains was identified in one patient with severe WAS. He developed pneumonia with hepatosplenomegaly at 2 months of age caused by CMV. As microcephaly was observed at birth, congenital CMV infection cannot be excluded. Previous studies described CMV infection in patients with WAS both prior to and following HSCT [10, 18-20], and it resulted in a fatal outcome in the majority of cases. The treatment guideline for CMV infection in patients with WAS, however, has not been well established.