Shwachman syndrome: Phenotypic manifestations of sibling sets and isolatedcases in a large patient cohort are similar

Objectives: With the use of clinical data from a large international cohort , we evaluated and compared affected siblings and isolated cases. Study design: Data from 116 families were collected, and patients conformin g to our predetermined diagnostic criteria were analyzed. Phenotypic manife stations of affected siblings and singletons were compared with the use oft tests, Wilcoxon scores, and chi(2) analysis. Results: Eighty-eight patients (33 female, 55 male; median age 5.20 years) fulfilled our predetermined diagnostic criteria for Shwachman syndrome; 63 patients were isolated cases, and 25 affected siblings were from 12 multipl ex families. Steatorrhea was present in 86% (57 of 66), and 91% (78 of 86) displayed a low serum trypsinogen concentration. Patients older than 4 year s more often had pancreatic sufficiency. Neutropenia occurred in 98%, anemi a in 42%, and thrombocytopenia in 34%. Myelodysplasia or cytogenetic abnorm alities were reported in 7 patients. Short stature with normal nutritional status was a prominent feature. Conclusions: Clinical features among patients with Shwachman syndrome varie d between patients and with age. Similarities in phenotype between isolated cases and affected sibling sets support the hypothesis that Shwachman synd rome is a single disease entity.