A variant of the Sebastian platelet syndrome with unique neutrophil inclusions.

The Sebastian platelet syndrome (SPS) is a hereditary giant platelet disorder characterized by thrombocytopenia and the presence of neutrophil inclusions identical to those present in neutrophils of patients with another giant platelet disorder, the Fechtner platelet syndrome (FPS). Patients with SPS differ from those with FPS in that they lack the clinical features of the Alport syndrome (high frequency hearing loss, congenital cataracts and chronic interstitial nephritis). The present study has evaluated six patients who resemble individuals with SPS, but have uniquely different neutrophil inclusions. Ultrastructural features of the neutrophil inclusions of the new variant are presented and compared with those found in other giant platelet disorders including classic SPS, FPS and the May-Hegglin anomaly, as well as the Chediak-Higashi syndrome.