Kenny-Caffey Syndrome, Type 2

Background and History: 

This is likely a hereditary disorder of the endocrine system, specifically that of the parathyroid gland which does not manufacture sufficient quantities of the parathyroid hormone.     

Clinical Correlations: 

Infants are born with a low birth weight and the head seems abnormally large perhaps because of this.  Shortness of stature is characteristic throughout life.  One patient has had cataracts at birth but it is unknown whether this is more than an isolated case.  In one patient where tissue was available for microscopic study there was deposition of calcium in the cornea and the retina.  The eyes are abnormally small and for this reason individuals are significantly farsighted.  In yet other patients, the optic nerves appear swollen and retinal vessels are abnormally tortuous and dilated.

The ‘soft spot’ on top of the head is slow to close.  Scalp hair is sparse.  The long bones of the arms and legs have an unusual morphology on X-ray with apparent thickening of the tubular portions.  Males often have small testicles but there is no evidence regarding their fertility.  Brain imaging shows abnormal deposition of calcium in various parts of the brain.  Intelligence seems to be normal.

Testing of the blood shows low calcium and elevated levels of phosphorous as seen in conditions in which there is a problem with the action of the parathyroid hormone.

Genetics: 

Several affected mothers have given birth to affected offspring of both sexes consistent with autosomal dominant inheritance.  Changes (mutations) in a single member of a pair of genes have been found in multiple individuals which is also consistent with this mode of inheritance.  Thus offspring of an affected parent has a 50% risk of inheriting this condition.

Diagnosis and Prognosis: 

This is an extremely rare condition and it is unlikely that the diagnosis can be made without doing blood work to detect the levels of calcium and phosphorous.  The constellation of findings in children can suggest Kenny-Caffey syndrome to experienced pediatricians and geneticists though.  An ophthalmological evaluation is indicated for it might corroborate the diagnosis.  An insufficient number of individuals have been studied to document the longevity but death in the first two decades of life has been reported in a number of individuals.

Additional Information
Inheritance/Pedigree: 
Autosomal dominant