What characteristics do patients with VMOS have in common?
Children with ELMO2 mutations are normal at birth but swelling in bones of head and face may appear beginning from as early as age 2. These swellings are a result abnormal blood vessels in bones and usually continue to slowly expand. The expansion would speed up during puberty. These swellings are asymmetric and can affect different parts head in different children. These swellings may squeeze, compress or deform important organs such as teeth, nose, eyes and brain. As these swellings are filled with fragile blood vessels they may bleed from time to time and sometimes cause massive bleeding which you should be very careful about. Abnormal shape or swelling of belly button can also be seen in most, but not all of people with VMOS. The continious slow bleeding can cause anemia.
How do doctors understand my child has VMOS?
A doctor may suspect VMOS when they see the general characteristics of the disease mentioned above. However, these will not be enough to make a diagnosis of the disease as there are diseases with similar appearance to VMOS. The doctor will probably want to examine the bones by a CT scan or MRI, and may sometimes ask for a view of the blood vessels in head and face called angiography or a small sample taken from the bones called a biopsy.
VMOS is a very rare genetic disease that appears as a result of the malfunction of a gene called ELMO2. It is usually seen in children of parents who are close relatives, such as cousins. A doctor may ask for a blood test from your child and the parents to determine the genetic change in ELMO2 gene and provide a definitive diagnosis.
An extensive description of the broad clinical spectrum of VMOS can be found in the section Professionals – Clinical characteristics .
Management of Clinical Manifestations
There is unfortunately no definitive cure for VMOS yet. However, with experience gained from few individuals with VMOS medical proffesionals can provide a follow-up for early detection and management of serious health problems. If needed, the swellings in VMOS can be removed by plastic surgery, so it is most appropriate that a team of proffesionals lead by a plastic surgeon will check the swellings in regular intervals. These proffesionals will check how much the swellings expand and where they are, to decide if they are compressing an important organ in head. If they find a serious compression they may offer you a surgery to remove the affected bone tissue and relax the compressed organ. Full mouth-tooth extracton might be required.
Another problem with VMOS can be the bleeding through the abnormal blood vessels that make up the bony swellings. Slow bleeding would result in anemia which can be treated at home. However, sudden massive bleeding may be life-threatening and in case of such a situation you should seek immediate medical attention. Surgery for removal of the affected bone tissue before such a massive bleeding event may be offered to prevent the life-threatening condition.
Genetic Counselling
VMOS is a genetic disorder and if you are willing, you should also ask for advice from a genetic counselor or medical geneticist. They may offer blood tests to detect ELMO2 mutations and provide you with information on how VMOS runs in families.
VMOS has an autosomal recessive inheritance pattern. This means two things: 1) People can be carriers of this disease and completely healthy, 2) For a disease to occur in a child both parents must be at least the carrier of the disease. Today more than 4,000 autosomal recessive genetic disorders are known. As carriers for most of these diseases are very rare it is usually unlikely for carriers of the same disease to have a baby. However, as same genetic diseases are carried in the same families or ethnic groups, these diseases are much more likely to appear in children born to parents who are related or from same ethnic group/location. When the parents are both healthy carriers of VMOS, there is 25% chance that the disease will appear in their next child. When one parent has VMOS and the other is a carrier, the chances that their children will have VMOS is 50%.
It may be possible to detect VMOS in a baby during pregnancy through genetic testing of the baby itself. However, testing during pregnancy for VMOS poses a challenge as the disease may or may not cause serious health problems earlier in life.
Thus, genetic counselling is crucial and each couple should be managed on a case by case basis, considering the specific needs of the family.
When VMOS is detected in a family member, if possible other family members, especially those who are married to a relative, should be offered a genetic testing for carrier status.