Gracile Bone Dysplasia

Background and History: 

This disorder is likely a form of hereditary parathyroid gland malfunction in which the bones are severely affected and some internal organs are malformed or dysfunctional. 

Clinical Correlations: 

Intrauterine development is retarded and infants are short in length primarily because the long bones of the arms and legs are short.  Some embryos die in utero and many others do not survive infancy.  The abdomen may be filled with fluid (ascites) and the spleen may be absent or malformed.

The skull is malformed and facies can be mildly distorted with a high forehead, and a depressed nasal bridge, while fusion of cranial bones can be abnormal.  The ribs are also abnormal and the lungs may not develop normally leading to breathing difficulties.  The eyes are usually small and some do not develop an iris (colored part of the eye that forms the pupil).  There may be malformations of the genitalia in both sexes.  Failure to thrive is common and seizures may occur.  The blood has low levels of calcium.


A gene change (mutation) in a specific gene has been found in a number of individuals.  The disorder is most likely inherited in an autosomal dominant pattern but limited reproductive capability prevents conclusive documentation.

Diagnosis and Prognosis: 

While the diagnostic features are evident at birth, this condition is extremely rare and difficult to recognize.  A collaborative approach with pediatricians, geneticists, orthopedists, endocrinologists, and ophthalmologists is necessary.  The sometimes life-threatening nature of the deformities adds urgency to the evaluation as well.

No treatment has been reported and is unlikely to reverse the in utero developmental anomalies.   Some benefit may be derived from correction of the low calcium levels or the use of parathyroid hormone.

Additional Information
Autosomal dominant