Platelet Ultrastructural Morphology and Morphometry in 10 Patients with MYH9- Related Disease - Abstract
MYH9-related disease is an autosomal dominant hereditary macro thrombocytopenia caused by mutations in the MYH9 gene which encodes the non-muscular myosin heavy chain type IIA. The patients have mild clinical bleeding, grayish-blue inclusions in granulocytes and, in some cases, nephropathy, neurosensory deafness, and cataracts. The aim of our study was to assess the platelet ultra structure in MYH9-related disease with the help of morphometry.
Ten patients with genetically confirmed MYH9-related disease were studied together with a group of 15 healthy individuals. The ultra structure of a minimum of 150 platelet sections for each patient was examined, and the morphometry of the main platelet traits was performed. We measured the size and shape of resting platelets, the diameter, number per platelet and number per unit of platelet area of the granules, dense bodies, mitochondria and lipid droplets. Moreover, we measured the percentage of platelet area occupied by open canalicular system and by glycogen masses. We compare the results
between patients and controls using the one-way analysis of variance.
We confirmed that MYH9-RD platelets are larger and rounder than normal platelets and they show expanded open canalicular system and increased membrane complexes. Moreover, we found that the size of ?-granules and dense bodies was enlarged, and the amounts of mitochondria and glycogen, both
related to cell energy metabolism, were significantly increased.