Electron microscopic and functional studies on platelets in gray platelet syndrome.

Area of Science:

• Hematology
• Genetics
• Cell Biology

Background:

• Gray platelet syndrome (GPS) is a rare inherited bleeding disorder.
• It is characterized by a deficiency of alpha-granules in platelets and their precursors, megakaryocytes.
• The clinical manifestations include prolonged bleeding time and impaired platelet aggregation.

Purpose of the Study:

• To investigate the ultrastructure and function of platelets and megakaryocytes in patients with GPS.
• To determine the mode of inheritance of GPS in an affected family.
• To identify morphological abnormalities associated with alpha-granule deficiency.

Main Methods:

• Hemostatic examinations (bleeding time, platelet retention, and aggregation studies).
• Analysis of ATP and ADP release.
• May-Giemsa staining of peripheral blood and bone marrow smears.
• Electron microscopy of platelets and megakaryocytes.

Main Results:

• Patients exhibited prolonged bleeding time, reduced platelet retention and aggregation, and diminished ATP/ADP release.
• Platelets and megakaryocytes showed a characteristic gray color due to alpha-granule deficiency.
• Electron microscopy revealed enlarged platelets with fewer alpha-granules, normal dense bodies and mitochondria, and various morphological abnormalities.
• Megakaryocytes had defective alpha-granule synthesis.

Conclusions:

• Gray platelet syndrome is an autosomal dominant disorder.
• The primary defect involves deficient alpha-granule synthesis and content in platelets and megakaryocytes.
• Morphological abnormalities in platelets are associated with the alpha-granule deficiency.