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.

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