Detailed Definition

Skeletal dysplasias are genetic disorders of skeletal growth affecting bones and cartilage. Most of the skeletal dysplasias cause short stature or dwarfism and other bone deformities. These changes in bone structure can also impact other body systems. Skeletal dysplasias tend to cause disproportionate dwarfism and do not include proportionate dwarfism due to growth hormone

deficiency. Individuals with skeletal dysplasias almost always have normal intelligence.

Causes/Types

Over 200 types of skeletal dysplasias have been described and classified, most being extremely rare.  Some of the more common diagnoses include achondroplasia, cartilage hair hypoplasia, diastrophic dysplasia, hypochondroplasia, Morquio syndrome, multiple epiphyseal dysplasia (MED), pseudoachondroplasia, and spondyloepiphyseal dysplasia congenita (SEDc).

Diagnosis

Most of the skeletal dysplasias are diagnosed by clinical and radiological (x-ray) features.  For many conditions, the involved genes have been identified and genetic testing may be available.  Genetic testing is often used to confirm a suspected diagnosis, differentiate between two possible diagnoses, and to diagnose the skeletal dysplasia prenatally (in utero).

Treatment/Services

Since establishing the Northern California Skeletal Dysplasia Clinic in 1997, in cooperation with Children's Hospital Oakland, Kaiser Permanente has been able to offer comprehensive, state-of-the-art, care to its members with skeletal dysplasias. The clinic setting provides a forum for diagnosis and treatment of skeletal dysplasias throughout the lifespan. Our multidisciplinary approach offers patients a unique opportunity to have all their medical needs assessed together, as a whole, by a wide variety of specialists. These providers then meet together, after their evaluations, in order to discuss each individual's needs and how best to coordinate their care. The recommendations generated from these post-clinic conferences have the benefit of multiple perspectives and the varied experiences of each of the providers attending.

In addition to holding 10 regional clinics every year, the Northern California Skeletal Dysplasia Clinic provides case management services in order to coordinate care, ensure timely follow-up on recommendations and assist families with issues that come up in between clinic visits. Our goal is to optimize the physical, social, and psychological well-being of our patients and their families.

Some of the most difficult aspects of having a skeletal dysplasia are not the medical issues, but rather the environmental and social issues that arise for a person of short stature and/or with an orthopedic disability.  It is important to work with the family on their adjustment to the diagnosis and what that will mean for the child and their family. Individuals with skeletal dysplasias and their families should receive assistance in developing strategies for functioning in a world made for taller people. Participation in household, school, and social activities are examples of activities that may all be significantly impacted by the condition.  Stools, extenders for reaching, and extra time to get to class, are all examples of modifications that may be required.  In addition to the functional aspects, being short-statured and orthopedically handicapped carries great stigma.  It is important to help the people with skeletal dysplasias and their families to mentally and emotionally prepare themselves for the teasing, staring, and ignorance they may face and to learn coping mechanisms and reactions to these behaviors.  Little People of America (LPA) is the support organization for all people of short stature and their families.  This organization can be extremely helpful in assisting with social adjustment and, more than anything else, letting people with short stature know that they are not alone in their circumstances.

Prenatal Diagnosis:
For general information, please see Prenatal Diagnosis under Genetic Counseling.  Prenatal diagnosis is now available for many of the more common skeletal dysplasias by DNA analysis.  Invasive tests (e.g., chorionic villi sampling and amniocentesis) can be offered early in pregnancy (before 20 weeks) when one or both parents have a skeletal dysplasia and a mutation for their condition(s) can be identified.  It can also be offered to couples who have had a previous child with the skeletal dysplasia.

Ultrasound is often able to detect skeletal dysplasias in utero.  Lethal and severe skeletal dysplasias may be identified in the second trimester while some of the more mild forms, such as achondroplasia, often cannot be detected until the third trimester.  Some skeletal dysplasias are not detectable by ultrasound as their features do not present until infancy or even later in childhood.  If a skeletal dysplasias noted by ultrasound, invasive prenatal testing may be offered to determine whether or not the fetus has a lethal skeletal dysplasia or to confirm a suspected diagnosis.

Other Information

Please see our Skeletal Dysplasia Clinic program highlights page for more information.