Understanding Skeletal Dysplasia

WHAT IS SKELETAL DYSPLASIA?

More commonly known as dwarfism, skeletal dysplasia is a complex grouping of 350+ bone and cartilage disorders that affect the fetal skeleton as it develops in utero.

Although skeletal dysplasias are relatively uncommon, collectively the birth incidence of these disorders is nearly one in every 4,000-5,000 births. Due to this rarity, limited research has been conducted on the gene code that controls bone growth, which means only a small handful of skeletal dysplasia types have had their gene codes mapped successfully.

WHAT ARE ITS CAUSES?

The causes of skeletal dysplasias are nearly as diverse as the number of distinct disorders. Generally, however, the causes can be cataloged into three groups:

  • Genetically inherited as dominant or recessive traits or X-linked disorders
  • The result of spontaneous mutations
  • Secondary to exposure to a toxic substance or infectious agents resulting in abnormal skeletal development

Nearly half of the documented skeletal dysplasias are caused by a genetic mutation that makes prenatal diagnosis possible through genetic testing.

HOW IS IT EVALUATED & DIAGNOSED?

The fetal skeleton is usually evaluated as part of a routine ultrasound around week 20 of the pregnancy.

However, prenatal diagnosis of skeletal dysplasias remains challenging, especially when there is no family history of the disorders. This is because:

  • Each dysplasia type is equally rare and unique. Some display the same physical characteristics, but present different genetic abnormalities. Conversely, others display different physical characteristics, yet have similar molecular structures.
  • Some dysplasias are not apparent during the second trimester ultrasound, only becoming evident in the third trimester, or even after birth, further complicating timely diagnosis.
  • Ultrasound remains a limited imaging tool, even in the most experienced hands. Studies have indicated ultrasound has sensitivity in the range of 40 to 60 percent.

HELP US FIND A CURE

The Luca John Foundation is dedicated to ending for skeletal dysplasia and honoring those for whom a cure was too late.
Please consider making a contribution to our cause. Each dollar raised is a step closer to reaching our goal.

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