Objective :
To demonstrate a diagnosis by process of elimination, using a
case study of McCune Albright Syndrome.
Method and Background:
A case of McCune-Albright Syndrome in a 5 week old girl - an exercise in elimination of more obvious causes. McCune Albright syndrome (MAS). A rare multi-system genetic disorder, caused by a somatic (post-fertilisation) mutation in the Ga-stimulatory protein of the adenyl cyclase pathway. This results in protein hormone receptors being activated, causing continual function of the affected organ. Diagnosis is made by the presence of two of three clinical indicators, 1. Café-au-lait markings on skin, 2. Autonomous endocrine hyperfunction, 3. Polyostotic fibrous dysplasia,
Results:
LC,
a 5 week-old female, presented with jaundice and failure to thrive. She had
hypertension, diarrhoea and a large birthmark on her back (café-au-lait).
Patient had hyperbilirubinaemia, predominantly conjugated. Her thyroid testing
showed a very high Free T4 and Free T3 and very low TSH, consistent with a
hyperthyroid state. Thyroid antibodies were low.
Discussion:
The raised conjugated bilirubin eliminates breast milk jaundice, and suggests liver involvement. The low Thyroid Ab eliminates an autoimmune disease. These, with the Café-au-lait markings, confirm McCune Albright Syndrome.