CAMT is a serious and often life threatening genetic disorder. It leads to bleeding problems that are typically present from birth. A timely stem cell transplant is the only cure.
Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare and serious inherited genetic disorder. It often leads to bleeding and low counts of many types of blood cells.
“Congenital” means a trait or condition is present when you’re born.
Megakaryocytes are cells that help your body make platelets. The term “amegakaryocytic” in CAMT means you have few or no megakaryocytes.
Platelets, aka thrombocytes, are responsible for blood clotting. If your platelet count is low, it’s called thrombocytopenia.
Let’s examine what causes CAMT and what doctors can do about it.
CAMT occurs from a change (mutation) in your genes. Based on the gene responsible, doctors can split CAMT into two categories: CAMT-MPL and CAMT-THPO.
Your THPO gene is responsible for your liver’s production of the hormone thrombopoietin, which tells your body to make megakaryocytes. These megakaryocytes, in turn, make platelets.
When your body makes thrombopoietin, this hormone connects to other cells with a specific receptor. Instructions for how to make this receptor are found in your MPL gene.
Mutations to either gene can lead to a lack of megakaryocytes. Both types of mutations can lead to CAMT with many of the same symptoms, but the timing and treatment options are different.
CAMT is an inherited genetic condition. This means it occurs from the combination of genes you get from your biological parents.
It’s also an autosomal recessive disease. This means you need two copies of the mutation (one from each parent) that causes CAMT to have the condition.
If you have only one copy, you are a carrier of CAMT. You won’t have the disease, but you can have children with CAMT if the other parent also has the mutation.
It’s possible to be a carrier of CAMT and not know it. If you have relatives with CAMT, you might consider genetic counseling to learn whether you’re a carrier.
Anyone can have CAMT. Doctors typically discover it within the first month after birth.
It may be more common if you have a family history of CAMT or other forms of thrombocytopenia.
Experts have reported that CAMT is slightly
CAMT has also been found in consanguineous families, or those in which the parents are related. Such family structures are uncommon in the United States but may be more common in other parts of the world.
In people with CAMT, there is generally a severe lack of platelets at birth. This can lead to bleeding problems during the first month of life. In some cases, symptoms may begin before birth.
Some symptoms of CAMT include:
- bleeding beneath your skin
- bleeding in your skull or brain
- rectal bleeding, especially multiple episodes
- pulmonary hemorrhage
Sometimes neurological symptoms and developmental delays have been noted with CAMT. These can include:
- crossed eyes
- missing cerebellum
- underdeveloped corpus callosum and brain stem
- cortical dysplasia (abnormal brain development)
- structural abnormalities in the face
These symptoms might be the result of MPL gene mutations or the result of lasting damage from bleeding within the brain.
When do symptoms of CAMT begin to appear?
Symptoms of CAMT can begin before a baby is born, though it might not always be obvious.
Obvious bleeding typically occurs within the first day after birth. Symptoms are present within the first month for nearly everyone with CAMT.
The main way doctors diagnose CAMT is to take a bone marrow biopsy.
Many types of thrombocytopenia can affect newborns. A bone marrow biopsy can help doctors determine whether CAMT is the cause.
A family history of CAMT or other forms of thrombocytopenia might also help doctors reach a diagnosis.
If the biopsy shows a lack of megakaryocytes, further genetic testing might be used to confirm a diagnosis of CAMT.
Treatment for CAMT depends on whether you have CAMT-MPL or CAMT-THPO.
CAMT-MPL is more common. The main treatment is allogeneic hematopoietic stem cell transplant (HSCT). This type of stem cell can turn into any type of blood cell. It can come from donors who are genetically similar (but not identical twins).
HSCT can be a cure for CAMT. Doctors tend to consider it as early as possible, usually before age 3 years. Complications from HSCT can be fatal
CAMT often eventually develops into pancytopenia. It’s a serious and life threatening condition in which you don’t have enough red blood cells or white blood cells. This is in addition to not having enough platelets.
Once pancytopenia has set in, it might not be possible to diagnose CAMT if it has not been diagnosed already, making it more difficult to treat.
If doctors plan to use HSCT as a treatment method, they need to complete the procedure before pancytopenia sets in.
The outlook for people with CAMT is usually poor. Treatment — especially HSCT before pancytopenia develops — is necessary for someone with CAMT to reach adulthood.
Hemorrhaging or bone marrow problems are common in early childhood. They can lead to more severe complications or death.
CAMT is a very rare and serious genetic condition. You inherit CAMT if both parents carry a specific faulty gene. You can be a carrier of CAMT without any signs or symptoms.
CAMT leads to bleeding problems within the first days after birth due to a lack of platelets. For the more common type of CAMT, a stem cell transplant is usually the best available treatment.