An inherited genetic disorder that causes low platelets (thrombocytopenia) and giant platelets is called May-Hegglin anomaly (MHA). People who are born with this condition have a mutation in their MYH9 gene. Moreover, those who suffer from MHA are at increased risk of bruising or bleeding if they are injured. Most of the time, MHA is not severe enough to cause serious health problems.
In other words, a rare inherited genetic disorder that causes the body to produce abnormally large platelets and reduced platelets is called May-Hegglin anomaly. Normally, platelets are a type of blood cell that helps form clots that stop bleeding when a person is injured. Furthermore, people with MHA are more likely to experience hemorrhage (blood loss) after a major surgery than people without it. However, in most cases, people with this condition do not experience symptoms or major health problems. In any case, it is important to know you have this genetic disorder, as doctors can take steps to reduce the risk of injury or blood loss.
In general, this condition occurs quite rarely, with fewer than 200 cases reported in medical studies. That’s why doctors usually do not suspect it. Most of the time, it is diagnosed by ruling out other conditions that negatively affect the production of platelets before diagnosing MHA.
What is The Triad of May-Hegglin Anomaly?
Usually, this genetic disorder causes three distinct features. Examples include:
- Macrothrombocytopenia (abnormally large platelets)
- Thrombocytopenia (reduced production of platelets)
- Small rod-shaped structures inside the leukocytes – This is a type of white blood cell known as Dohle bodies.
The previous features often distinguish MHA from other conditions that cause abnormal platelets.
Symptoms
Commonly, people with MHA do not experience any symptoms because they have enough platelets to stop excessive bleeding. However, if you have symptoms, doctors may perform tests to check the platelet level in the blood. Check some examples below:
- Menorrhagia (heavy menstrual periods)
- Epistaxis (frequent nosebleeds)
- Easy bruising and bleeding
- Purpura (purple, red, or brown spots on the skin)
- Heavy bleeding (especially after surgery, dental procedure, or delivering a baby)
- Bleeding gums
If any of the previous symptoms occur, immediately contact your healthcare professional for a diagnosis and treatment.
Causes and Risk Factors
This condition occurs due to a gene mutation (MYH9 gene) that often passes from one of the biological parents during pregnancy. This gene is responsible for producing platelets that help clot the blood and stop bleeding. However, in people with MHA, the platelets are too large and abnormally shaped. Moreover, this abnormal gene may also reduce the production of healthy platelets, which significantly increases the risk of heavy bleeding (especially after surgery). This condition is inherited in an autosomal dominant pattern, which means one copy of the mutated MYH9 gene is enough to develop the disorder.
In addition, healthcare professionals have identified some factors that could elevate your risk of developing May-Hegglin anomaly. Examples include:
- Family history – If you have a parent or sibling with MHA, your risk of developing it significantly increases.
- Ethnicity – This condition affects individuals of Greek or Italian descent mostly. However, it may also affect other ethnicities.
- Pregnancy risk – Usually, MHA is diagnosed in pregnant women during routine blood tests (including a complete blood count or CBC). In some cases, MHA can be mistaken for pregnancy-related thrombocytopenia.
- New mutations – In about 30% of cases, MHA is not inherited from one of the biological parents, but due to a new, spontaneous gene mutation.
What Happens if the May-Hegglin Anomaly is Left Untreated?
People who ignore the symptoms may experience serious complications. That’s why it is important to know and manage MHA if you have it. Check some complications below:
- Bleeding disorders
- Surgical and obstetrical risk – Some people need prophylactic platelet transfusion due to heavy bleeding that may occur during surgery or postpartum.
- Renal disease – Without treatment, there is an increased risk of developing progressive nephropathy (such as FSGS – focal segmental glomerulosclerosis). This complication may lead to renal failure.
- Sensory impairment – These include sensorineural hearing loss and presenile cataracts.
- Misdiagnosis – MHA is frequently misdiagnosed as immune thrombocytopenic purpura (ITP).
This document does not contain all possible MHA complications, but you can consult with your healthcare professional about ways to reduce the risk of the previous ones.
How to Prevent May-Hegglin Anomaly?
Unfortunately, there is no way to prevent MHA from happening. However, you can perform genetic tests before pregnancy to make sure you do not have the abnormal MYH9 gene that causes this disorder. In general, there are 50% chance of passing the abnormal gene to your baby. Sometimes, a genetic counselor may help you assess potential risks. It is very important to understand the risks of having children with MHA.
Diagnosis
Most of the time, people with MHA do not realize they have this condition until a blood test done for other reasons shows a low platelet count and abnormally large platelets. For instance, you may identify any of the MHA features during a routine blood work to screen for health problems during pregnancy. Check below for other tests also used to diagnose MHA:
- Complete blood count (CBC) – This test is used to check the platelet level in the blood. In people with MHA, there are between 40,000 and 80,000 platelets per microliter of blood. However, lower than 150,000 platelets per microliter is considered low.
- Peripheral blood smear (PBS) – This is another type of blood test used to detect giant platelets. Doctors may also check for Dohle bodies in the leukocytes.
- Genetic tests – To perform this test, doctors will take a blood sample. It helps detect the abnormal MYH9 gene that is often present in people with MHA.
Sometimes, physicians may recognize other signs of low platelets (including increasing bleeding time).
Treatment
Most of the time, people with this genetic disorder do not have any symptoms that require treatment. However, your doctor should take extra precautions to prevent blood loss (such as after surgery). For instance, they may give you an intravenous (IV) desmopressin or a platelet transfusion before the medical procedure. People with MHA usually need a platelet transfusion to restore their levels for an emergency blood loss.
Moreover, additional monitoring is needed for pregnant women to prevent serious complications during delivery. Your healthcare professional may also recommend some tips to protect you and your baby.
Frequently Asked Questions
How do I take care of myself?
Doctors often recommend avoiding medicines that interfere with platelets, proper dental care, avoiding activities that lead to injury, and working closely with your pregnancy provider to monitor your health.
What is a MYH9-related disorder?
While May-Hegglin anomaly is a MYH9-related disorder, researchers show that there are other disorders that cause abnormal platelets and low platelets and involve mutations in the MYH9 gene. For example, Epstein syndrome, Fechtner syndrome, and Sebastian syndrome.
What can I expect if I have May-Hegglin anomaly?
Once you are diagnosed with this condition, you will need to take extra precautions to prevent injuries and manage it for the rest of your life. While most of the time MHA does not interfere with people’s lives, some of them may experience mild symptoms. If you have any other questions, ask your healthcare provider.
