Albinism
Platelet Dysfunction
Ceriod Accumulation
Inflammatory Bowel Disease
Pulmonary Fibrosis
ALBINISM 
The type of albinism in HPS is a tyrosinase-positive form, which
means that individuals may present with varied amounts of pigmentation.
Some persons may have very light hair and fair features
(oculocutaneous albinism or OCA), while others may have dark hair
with albinism in their eyes only. (ocular albinism or OA).
| Both of these children have Hermansky-Pudlak Syndrome | |
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The visual impairment inherent in HPS persons is the same as in other types of albinism. It is a result of the lack of pigment during eye development. This has a consequence of decreased acuity which is frequently severe enough to be legal blindness, photophobia (light sensitivity), strabismus (crossed eyes), and nystagmus (involuntary movement of the eyes).
PLATELET DYSFUNCTION
WHY DO WE BLEED?
Use of aspirin, ibuprofen and drugs (both prescription and over the counter) that effect platelet function can make the bleeding tendency worse! Ask your doctor and your pharmacist before taking medications.
Hermansky-Pudlak syndrome involves a bleeding disorder caused by a platelet defect.
Platelets are involved in one of the mechanisms that exist within the body to counteract bleeding. They are made in the bone marrow and circulate in the bloodstream in large quantities. They act directly to plug small leaks in vessels by clumping (aggregating) and obstructing flow, and indirectly by releasing substances that trigger a chain of events that culminates in a clot.
These chemical substances ( ADP, serotonin, calcium, ATP ) are normally stored in platelet dense granules. These dense granules are little sacs or compartments that are in the platelet membrane. Filled with the stored chemicals they look like "chips" and the platelets appear to look like a "chocolate chip cookie" under an electron microscope. These chemical substance are destined to be released to assist in clotting. In Hermansky-Pudlak syndrome, these dense granules are missing. Therefore, no substances are released. The platelets appear to look
| Chocolate Chip | Butter Cookie |
|
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| Normal Platelet | HPS Platelet |
like a "butter cookie" instead of a "chocolate chip cookie" under an electron microscope.
Standard laboratory blood test results are not abnormal in HPS. Prothrombin time (PT), partial thromboplastin time (PTT), and platelet counts are all normal in HPS. Bleeding times can be normal though they are often prolonged. The clinical result of the defect in HPS can be seen in a bleeding tendency that varies from quite mild and hardly noticeable to life threatening. There is a possibility that those persons with HPS that encounter severe bleeding problems might also have a decrease in platelet von Willebrand's factor activity, another blood component responsible for normal clotting.
Viewing prepared platelets under the electron microscope is the only definitive diagnostic test for HPS at this time. The HPS platelets lack dense bodies. Since all the genetic variants of HPS have not been identified as yet, diagnosis through molecular analysis is not comprehensive.
WHAT ARE THE SYMPTOMS OF PLATELET DYSFUNCTION?
Persons with HPS may have a tendency to bruise easily. They may experience frequent nosebleeds or when cut, tend to bleed longer. Other persons may have unusual bleeding episodes (e.g., heavy menstrual bleeding, bleeding with dental procedures). The amount of prolonged bleeding varies in individuals from very mild to life threatening.
"Ceroid" is the name given to a substance that is made by certain cells in the body. In persons with HPS, this substance, which is a poorly understood lipid protein material appears to accumulate in lysosomes. Lysosomes are structures inside cells that assist in normal chemical functions. Presently, it is thought that the accumulation of the ceroid is associated with difficulties that can arise in the colon (Inflammatory Bowel disease), lungs (Pulmonary Fibrosis) and kidneys. These difficulties can be in isolation of each other or together and all seem to progress with age.
When the intestines become affected it can cause a problem that resembles a common disease called Crohn's disease. Upon colonoscopy ( a procedure done using a scope to visualize the inside of the colon ) granulomas or sores may be seen skipped around the membrane of the colon.
WHAT ARE THE SYMPTOMS OF INFLAMMATORY BOWEL DISEASE?
It may cause diarrhea, weight loss, cramps and possibly blood in the stool.
A more common problem in Hermansky-Pudlak syndrome is lung disease. It seems that it may be dependent on which gene mutation of HPS is present. It is particularly prevalent in those individuals that are of Puerto Rican ancestry. Under investigation is the possibility that the accumulation of ceroid is associated with an inflammatory response in the lungs which eventfully scars the lung tissue and it losses its ability to expand and contract with the mechanisms of breathing. It begins to restrict the inflation of the lungs.
WHAT ARE THE SYMPTOMS OF PULMONARY FIBROSIS?
When lungs become affected, shortness of breath and abnormal fatigue with exertion might be a sign. One way it can be followed is through Pulmonary Function Tests (PFT) and the result of the Forced Vital Capacity (FVC).