Gray Platelet Syndrome (GPS)

 

Chromosome location:

(1) 3p21 if autosomal recessive inheritance

(2) 9q34 (gene for GFI1B) for autosomal dominant inheritance

 

Clinical features:

(1) mild to moderate bleeding disorder

(2) progression to myelofibrosis

(3) variable splenomegaly

 

Laboratory findings:

(1) thrombocytopenia with platelets larger than normal (“macrothrombocytopenia”)

(2) Platelets have a grayish appearance on light microscopy.

(3) There is an absence of alpha-granules in platelets on electron microscopy.

(4) Serum vitamin B12 is elevated (Gunay-Aygun et al).