Ellis-van Creveld syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at August 19, 2016
StartDiseasesEllis-van Creveld syndrome

Ellis–van Creveld syndrome is sometimes also called chondroectodermal dysplasia, mesoectodermal dysplasia, or simply EVS for short. EVS is a growth disorder that is inherited. It is a more severe form of Weyers acrofacial dysostosis, but the two conditions share the same basic set of symptoms. Ellis–van Creveld syndrome is considered a rare condition in the general population. It is classified alongside similar conditions as a type of short rib-polydactyly syndrome.

Contents

Definition & Facts

Ellis–van Creveld syndrome is named after two doctors, Richard W.B. Ellis and Simon van Creveld. Both practicing pediatricians, the two first identified Ellis–van Creveld syndrome in 1940. However, they did not name it after themselves. Rather, they decided to call the syndrome "chondroectodermal dysplasia."

Ellis–van Creveld syndrome is rare in the general population, affecting only one case in every 30,000 to 200,000 infants. However, there is one place where the syndrome is seen far more frequently: in the Amish community called "Old Order Amish" that currently lives in Pennsylvania.

Researchers call this unusual incidence evidence of the genetic drift theory. Genetic drift occurs when a population's gene pool becomes quite small and constrained for any number of reasons, such as a community where members are only permitted to pick a partner from within the same community.

An extreme form of this is called founder effect, which occurs when a small gene pool produces a large amount of certain recessive genes. It is now known that the founder effect is at the root of why there are so many cases of Ellis–van Creveld syndrome within the Old Order Amish community; all cases within the community have even been traced back to a single Amish couple.

Symptoms & Complaints

Ellis–van Creveld syndrome is first and foremost a condition of abnormal bone growth. The result of this abnormal growth pattern is dwarfism (short stature in adulthood), which is also the major symptom of the syndrome. Ellis–van Creveld syndrome causes a specific type of dwarfism called short limb dwarfism. This type of dwarfism is characterized by each of the following symptoms:

Causes

There are two different genes, EVC and EVC2, that can mutate to cause Ellis–van Creveld syndrome. These two genetic mutations are the culprits in about 50 percent of cases of the syndrome. However, the cause for the other 50 percent of cases still remains unknown.

To date, researchers know little about EVC and EVC2. However, both genes are suspected to regulate cell-to-cell communication during physical development. By interfering with normal communication, it is thought that the mutations in EVC and EVC2 can prevent normal fetal development during pregnancy.

Ultimately, heritable cases of Ellis–van Creveld syndrome are caused by an autosomal recessive condition, which means that both parents must contribute one or both genes linked to the syndrome in order to pass it along to their offspring. If only one parent passes along the gene, the child will be a genetic carrier.

Diagnosis & Tests

Diagnosis of Ellis–van Creveld syndrome can involve a number of different tests. Genetic testing may be done at any time to look for mutations in the EVC and EVC2 genes. Prenatal ultrasound tests can often detect the syndrome in the unborn infant. Once the infant is born, observation of symptoms as part of a physical examination or newborn screening is the chief method for diagnosing Ellis–van Creveld syndrome.

Often the first symptom to appear is polydactyly fingers and/or toes, which will be visible immediately. Natal teeth will also be visible at birth. Congenital heart defects will be detectable by a stethoscope test. Male patients may present with undescended testicles or an abnormal urine canal at birth. As the individual grows, growth delays and bone abnormalities will start to appear.

Treatment & Therapy

Treatment for Ellis–van Creveld syndrome can begin as soon as symptoms begin to arise. For infants that are born with respiratory or heart abnormalities, surgery may be immediately indicated. Natal teeth may be removed because they can get in the way of normal feedings. In some cases, while a treatment plan will likely be outlined immediately, some treatments will have to wait until the child gets a little older.

Typically, due to the array of abnormalities and complications that are associated with Ellis–van Creveld syndrome, the treatment team will include a variety of specialists including a pediatrician, pulmonologist, urologist, orthopedist, dentist/orthodontist, cardiologist, physical therapist, podiatrist and others as symptoms may indicate.

Unfortunately, there is no treatment for the syndrome itself, which means that treatment will always focus on controlling and easing symptoms.

Prevention & Prophylaxis

There is no way to prevent Ellis–van Creveld syndrome though prospective parents may decide to undergo genetic testing during family planning to assess the risk that their child may have the disorder. However, since only half of reported cases of Ellis–van Creveld syndrome can be traced back to heritable genes, such testing may not accurately reveal the probability of having an infant born with the syndrome.