Ellis-Van Creveld Dysplasia

This rare skeletal dysplasia was first described in 1940 by Richard W. Ellis and Simon van Creveld who coined the term “Chondro-ectodermal dysplasia” to illustrate the main features of this condition: ectodermal involvement (skin, hair and nails) and chondrodysplasia (cartilage and bone anomalies) (2).

 
How Ellis-Van Creveld Dysplasia Is Inherited

Ellis-van Creveld is transmitted in an autosomal recessive mode. The parents are of average stature and must both be carriers of the mutation.

 
Causes of Ellis-Van Creveld Dysplasia

Recent studies have found that mutations in two nonhomologous genes, positioned in a head-to-head configuration along chromosome 4 (4p16), are responsible for EVC (3).

 
Physical Characteristics

Ellis-Van Creveld Dysplasia is most common in the Amish people of Pennsylvania and the indigenous people of Western Australia. The incidence is estimated at 1 per 60,000 live births. More than 200 cases of EVC have now been reported (3).

Face & Skull
  • Dental abnormalities: natal teeth, partial or pseudocleft in the middle upper lip, small teeth, and delayed eruption
Trunk, Chest, & Spine:
  • No significant trunk abnormalities
  • No spinal malformation
  • Occasional short thorax at birth
  • Short and narrow rib cage
Arms & Legs:
What are the X-ray characteristics?

The radiographic features of EVC patients include progressive distal shortening of the long bones, with metaphyseal broadening. In infancy, pelvic dysplasia is common, along with low iliac wings and downward projections at the medial and lateral aspects of the acetabula. Pelvis configuration will normalize by childhood. Delayed ossification of the upper lateral portions of the proximal tibia will cause knock-knee. In young childhood, the epiphyseal ossification center is adjacent to the middle portion of the tibial metaphysis. Hypoplasia of the lateral epiphyses also occurs. The carpals are malformed, with fusion of the capitate and hamate. The middle phalanges are short and broad; hypoplasia of the distal phalanges is typical.

 
Making the Diagnosis

The condition can be diagnosed in the first trimester of pregnancy through an ultrasound scan looking for extra fingers or toes, cardiac defects, abnormalities of the kidneys and under-developed limbs. It has to be distinguished from related disorders such as Jeune Syndrome and the short-rib polydactyly syndromes. This could be possible only after birth. Radiographic features might also help with the diagnosis.

 
Musculoskeletal Problems
Polydactyly

Polydactyly will oftentimes require surgery so that the extra digit(s) can be removed. The surgery may be a soft-tissue or bony procedure, depending upon the underlying pathology.

Progressive Genu Valgus

Progressive genu valgus will require careful follow-up in the longer term, usually at 6-month to yearly intervals. Supporting the knee in a corrective knee brace is the initial management, but bracing does not obviate the need for surgery.

Surgery is advised for angulations greater than 20 degrees (less if the deformity is progressive in a young child). The bony deformity is corrected by an osteotomy and the leg is placed in an external fixator until the osteotomy heals. Recurrence over time is common and several corrective procedures may be necessary during childhood for severe deformities.

In the older child nearing the end of growth, an alternative strategy is to slow down growth of the inner aspect of the tibia by a metal staple or stop growth completely by surgical removal of the growth plate. Elevating the under-developed part of the tibia has been performed in selected cases to restore knee alignment.

 
Problems Elsewhere in the Body
Congenital Heart Defects

Congenital heart defects are seen in about 60% of children. The most common are an atrial septal defect, a single atrium, and a ventricular septal defect. Assessment by a pediatric cardiologist soon after birth is strongly recommended. Cardiac surgery may be needed to correct the abnormalities. Nearly 50% of babies born with EVC will die due to cardiorespiratory complications.

Genitourinary Anomalies

Genitourinary anomalies include poor development of the penis and kidneys. Evaluation by a paediatric urologist is advised.

Teeth

Teeth will appear early and may even be present at birth. They are small, peg-shaped and poorly formed. EVC patients are predisposed to dental cavities. Several abnormalities around the lips and gums have been described. Children with EVC would benefit from early referral to an orthodontist for surgical or prosthetic management of dental problems.

 
What to Look For

Congenital heart disease is common, therefore cardiologist consultation
is recommended.

Occasionally, abnormalities such as mental retardation, renal anomalies, Dandy-Walker cysts, hydrocephaly, situs inversus, and heterotopic masses of grey matter, have been reported.

Finally, generally all skeletal dysplasias warrant multidisciplinary attention. Regular assessment by an orthopedist, geneticist, pediatrician,
dentist, neurologist, and physical therapist will provide the most comprehensive treatment.

 
References
  1. Jones, Kenneth L. Recognizable Patterns of Human Malformation. Philadelphia, PA: Elsevier Saunders. 2006.
  2. Scott, Charles I. Dwarfism. Clinical Symposium, 1988; 40(1):17-18.
  3. Spranger, Jurgen W. Brill, Paula W. Poznanski, Andrew. Bone Dysplasias: An Atlas of Genetic Disorder of Skeletal Development. Oxford: Oxford University Press. 2002.

Trusted Insights from Nemours' KidsHealth

Genetic Counseling

If you and your partner are newly pregnant, you may be amazed at the number and variety of prenatal tests available to you. Blood tests, urine tests, monthly medical exams, diet questionnaires, and family history tracking — each helps to assess the health of you and your baby, and to predict any potential health risks.

Unlike your parents, you may also have the option of genetic testing. These tests identify the likelihood of passing certain genetic diseases or disorders (those caused by a defect in the genes — the tiny, DNA-containing units of heredity that determine the characteristics and functioning of the entire body) to your children.

Some of the more familiar genetic disorders are:

If your history suggests that genetic testing would be helpful, you may be referred to a genetic counselor. Or, you might decide to seek out genetic counseling yourself.

But what do genetic counselors do, and how can they help your family?

What Is Genetic Counseling?

Genetic counseling is the process of:

  • evaluating family history and medical records
  • ordering genetic tests
  • evaluating the results of this investigation
  • helping parents understand and reach decisions about what to do next

Genetic tests are done by analyzing small samples of blood or body tissues. They determine whether you, your partner, or your baby carry genes for certain inherited disorders.

Genes are made up of DNA molecules, which are the simplest building blocks of heredity. They're grouped together in specific patterns within a person's chromosomes, forming the unique "blueprint" for every physical and biological characteristic of that person.

Humans have 46 chromosomes, arranged in pairs in every living cell of our bodies. When the egg and sperm join at conception, half of each chromosomal pair is inherited from each parent. This newly formed combination of chromosomes then copies itself again and again during fetal growth and development, passing identical genetic information to each new cell in the growing fetus.

Current science suggests that human chromosomes carry from 25,000 to 35,000 genes. An error in just one gene (and in some instances, even the alteration of a single piece of DNA) can sometimes be the cause for a serious medical condition.

Some diseases, such as Huntington's disease (a degenerative nerve disease) and Marfan syndrome (a connective tissue disorder), can be inherited from just one parent. Most disorders, including cystic fibrosis, sickle cell anemia, and Tay-Sachs disease, cannot occur unless both the mother and father pass along the gene.

Other genetic conditions, such as Down syndrome, are usually not inherited. In general, they result from an error (mutation) in the cell division process during conception or fetal development. Still others, such as achondroplasia (the most common form of dwarfism), may either be inherited or the result of a genetic mutation.

Genetic tests don't yield easy-to-understand results. They can reveal the presence, absence, or malformation of genes or chromosomes. Deciphering what these complex tests mean is where a genetic counselor comes in.

About Genetic Counselors

Genetic counselors are professionals who have completed a master's program in medical genetics and counseling skills. They then pass a certification exam administered by the American Board of Genetic Counseling.

Genetic counselors can help identify and interpret the risks of an inherited disorder, explain inheritance patterns, suggest testing, and lay out possible scenarios. (They refer you to a doctor or a laboratory for the actual tests.) They will explain the meaning of the medical science involved, provide support, and address any emotional issues raised by the results of the genetic testing.

Who Should See One?

Most couples planning a pregnancy or who are expecting don't need genetic counseling. About 3% of babies are born with birth defects each year, according to the Centers for Disease Control and Prevention (CDC) — and of the malformations that do occur, the most common are also among the most treatable. Cleft palate and clubfoot, two of the more common birth defects, can be surgically repaired, as can many heart malformations.

The best time to seek genetic counseling is before becoming pregnant, when a counselor can help assess your risk factors. But even after you become pregnant, a meeting with a genetic counselor can still be helpful. For example, sometimes babies have been diagnosed with spina bifida before birth. Recent research suggests that delivering a baby with spina bifida via cesarean section (avoiding the trauma of travel through the birth canal) can minimize damage to the spine — and perhaps reduce the likelihood that the child will need a wheelchair.

Experts recommend that all pregnant women, regardless of age or circumstance, be offered genetic counseling and testing to screen for Down syndrome.

It's especially important to consider genetic counseling if any of the following risk factors apply to you:

  • a standard prenatal screening test (such as the alpha fetoprotein test) yields an abnormal result
  • an amniocentesis yields an unexpected result (such as a chromosomal defect in the unborn baby)
  • either parent or a close relative has an inherited disease or birth defect
  • either parent already has children with birth defects or genetic disorders
  • the mother-to-be has had two or more miscarriages or babies that died in infancy
  • the mother-to-be will be 35 or older when the baby is born. Chances of having a child with Down syndrome increase with the mother's age: a woman has a 1 in 350 chance of conceiving a child with Down syndrome at age 35, a 1 in 110 chance at age 40, and a 1 in 30 chance at age 45.
  • you are concerned about genetic defects that occur frequently in certain ethnic or racial groups. For example, couples of African descent are most at risk for having a child with sickle cell anemia; couples of central or eastern European Jewish (Ashekenazi), Cajun, or Irish descent may be carriers of Tay-Sachs disease; and couples of Italian, Greek, or Middle Eastern descent may carry the gene for thalassemia, a red blood cell disorder.

Meeting With a Genetic Counselor

Before you meet with a genetic counselor in person, you'll be asked to gather information about your family history. The counselor will want to know of any relatives with genetic disorders, multiple miscarriages, and early or unexplained deaths. The counselor will also want to look over your medical records, including any ultrasounds, prenatal test results, past pregnancies, and medications you may have taken before or during pregnancy.

If more tests are necessary, the counselor will help you set up those appointments and track the paperwork. When the results come in, the counselor will call you with the news and often will encourage you to come in for a discussion.

The counselor will study your records before meeting with you, so you can make the best use of your time together. During the session, you'll go over any gaps or potential problem areas in your family or medical history. The counselor can help you understand the inheritance patterns of any potential disorders and help assess your chances of having a child with those disorders.

The counselor will distinguish between risks that every pregnancy faces and risks that you personally face. Even if you discover you have a particular problem gene, science can't always predict the severity of the related disease. For instance, a child with cystic fibrosis can have debilitating lung problems or, less commonly, milder respiratory symptoms.

After Counseling

Genetic counselors can help you understand your options and adjust to any uncertainties you face, but you and your family will have to decide what to do next.

If you've learned prior to conception that you and/or your partner are at high risk for having a child with a severe or fatal defect, your options might include:

  • pre-implantation diagnosis — when eggs that have been fertilized in vitro (in a laboratory, outside of the womb) are tested for defects at the 8-cell (blastocyst) stage, and only nonaffected blastocysts are implanted in the uterus to establish a pregnancy
  • using donor sperm or donor eggs
  • adoption
  • taking the risk and having a child
  • establishing pregnancy and have specific prenatal testing

If you've received a diagnosis of a severe or fatal defect after conception, your options might include:

  • preparing yourself for the challenges you'll face when you have your baby
  • fetal surgery to repair the defect before birth (surgery can only be used to treat some defects, such as spina bifida or congenital diaphragmatic hernia, a hole in the diaphragm that can cause severely underdeveloped lungs. Most defects cannot be surgically repaired.)
  • ending the pregnancy

For some families, knowing that they'll have an infant with a severe or fatal genetic condition seems too much to bear. Other families are able to adapt to the news — and to the birth — remarkably well.

Genetic counselors can share the experiences they've had with other families in your situation. But they will not suggest a particular course of action. A good genetic counselor understands that what is right for one family may not be right for another.

Genetic counselors can, however, refer you to specialists for further help. For instance, many babies with Down syndrome are born with heart defects. Your counselor might encourage you to meet with a cardiologist to discuss heart surgery, and a neonatologist to discuss the care of a post-operative newborn. Genetic counselors can also refer you to social workers, support groups, or mental health professionals to help you adjust to and prepare for your complex new reality.

Finding a Genetic Counselor

Working with a genetic counselor can be reassuring and informative, especially if you or your partner have known risk factors. Talk to your doctor if you feel you would benefit from genetic counseling. Many doctors have a list of local genetic counselors with whom they work. You can also contact the National Society of Genetic Counselors for more information.

Reviewed by: Louis E. Bartoshesky, MD, MPH
Date reviewed: June 2010
Originally reviewed by: Linda Nicholson, MS, MC