Presenting features and platelet anomalies in WAS: one centre’s experience

To the Editor, In 2011, Moratto et al. [1]. identified age at haematopoietic stem cell transplantation (HSCT) as a risk modifier for complications inWiskott-Aldrich syndrome (WAS); of note, complications appear to be 1.5 times more likely in children transplanted at ages 2–5, compared to younger than 2 (RR = 1.53; CI, 0.90–2.58; P = 0.130). This reinforces the importance of prompt recognition, diagnosis and assessment for HSCT in patients with suspected WAS. We evaluated the presenting features in boys with WAS mutations transplanted at the Great North Childrens’ Hospital, Newcastle-upon-Tyne between 1989 and 2015 in order to identify any delay in diagnosis and causative factors, including misdiagnosis, and clarify the role of mean platelet volume in making a diagnosis of WAS. We sought to identify key discriminating diagnostic features in order to aid timely diagnosis and transplantation of these patients. Data was collected retrospectively from written and electronic medical records of 20 boys with WAS mutations, for which all families had given prior written consent. Information regarding date and nature of symptom onset, time elapsed until diagnosis, mean platelet volume at presentation, age at transplantation and outcome were recorded in an anonymised spreadsheet. Symptomatology was coded as one or more of the following: infectious and immunological, including autoimmunity; eczema; bruising and petechiae; and bleeding. No differentiation was made between WAS and XLT due to no significant difference in platelet counts, platelet size and bleeding episodes in these conditions. Median age at symptom onset was 2 months (birth – 9 months) and at diagnosis was 1 year (2 months – 14.1 years). Median interval between symptom onset and diagnosis was 8 months (2 weeks – 13.8 years). The most common presenting symptom was bleeding (13 reports, 65 %). The subsequent most common symptoms were bruising (11, 55 %); eczema and skin disease (9, 45 %) and immunological and infectious (7, 35 %). Initial documented impressions included nonaccidental injury [1], congenital cytomegalovirus infection [1] and suspected ITP [2]. The most common combination of symptoms at presentation was bruising with eczema, in 7 (35 %), bleeding and bruising, 5 (25 %); bleeding and eczema, 5 (25 %); bleeding and infective/immunological, 4 (20 %); bruising and infective or immunological, 4 (20 %), infective or immunological and eczema, 1 (5 %) patient. There was no documented family history of WAS or XLT. Eight patients (40 %) had a recorded mean platelet volume (MPV) following presentation to our unit. Median MPV was 4.85 fl (range: 3.6–21); only 3 patients had a volume < 5 fl (Fig. 1). One result was recorded as Blow^ and so was omitted from analysis. Our results show a lag between onset of symptoms and confirmed diagnosis of WAS of 8 months. A diagnostic delay in WAS (and other primary immunodeficiency disorders) of * Christo Tsilifis ctsilifis@gmail.com