Chediak-Higashi syndrome can also be found in killer whales.

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive mutation in the LYST gene. This results in microtubule defects in the cell that causes decreased phagocytosis. The decreased phagocytic activity of the cells in the body leads to recurrent pyogenic infections, skin pigmentation disorders and peripheral neuropathy. Manifestations include neutropenia, oculocutaneous albinism, periodontal disease, and bleeding disorders.

The bleeding disorders are heterogeneous. A study of 8 CHS patients by Al-Sheyyab, et.al. pointed out several mechanisms for the bleeding diathesis in CHS. In one patient, there is abnormal aggregation due to storage pool deficiency (SPD) of ADP and serotonin. In another patient, the aggregation defect resembles that of von Willebrand disease type IIb. Other defects involved the dense bodies and the alpha-granules as well as the platelet membrane.

An avenue of research in the pathophysiology of CHS is therefore opened up by these findings. What are the different platelet defects associated with CHS? What are the different mechanisms leading to an abnormality in platelet aggregation? What is the effect of ristocetin in platelet aggregation and how is this significant in CHS patients. The use of Impact-R will greatly aid the researcher in the investigation of the abovementioned issues.

What is a screening test? It is a device used to detect disease or a precursor of a disease in persons who do not have signs and symptoms. The decision to screen should be based on a careful history and assessment of risk factors.

Children with a family history of bleeding disorders may well benefit from a

Alexei Nikolaevich, heir to the Russian throne, had Hemophilia B.

screening test. The child’s future health and quality of life will depend on the diagnosis of a serious medical condition ahead of the time when signs and symptoms manifest. Children with a family history of congenital platelet function defects, clotting factor deficiencies, and defects in primary or secondary aggregation are among those that will put a screening test to good use.

A study by Revel-Vilk, et.al. evaluated the use of the Impact-R as a one such screening test. They concluded that the Impact-R is highly effective in excluding a bleeding disorder in patients with normal result. However, in case of abnormal Impact-R results, further testing is necessary to diagnose the condition.