GLA deficiency

The relatively common occurrence and the protean nature of Fabry disease has lead to its designation by some as the Great Imposter, replacing syphilis to which this term was previously applied.  Compounding the diagnostic difficulties in some individuals is the absence of the complete classical phenotype due to the presence of DNA variants that may modify the expression of some the clinical features.

Most signs present in the first or second decade of life with generally earlier onset in males.  The presence of proteinuria before the age of 20 years in the absence of other primary kidney disease should always raise the possibility of Fabry disease.  However, the diagnosis is often not made until the third decade in males and the fourth decade in females.  Glycosphingolipid inclusion deposits in endothelial cells are responsible for the systemic signs and symptoms including renal and heart disease which are the most common causes of premature death.  Small vessel involvement resulting in cerebrovascular disease and painful peripheral neuropathy can be debilitating. The risk of ischemic strokes is increased.  Cardiac manifestations include hypertrophic cardiomyopathy (60%), mainly involving the left ventricle, and dysfunction of the mitral and aortic valves (10 to 25%).  Dysfunction of renal glomeruli may progress to renal failure by the third to fifth decade in males.  The angiokeratomas and angiomas (most pronounced in a swimming trunk pattern) are secondary to vascular involvement of cutaneous vessels but are non-specific since they also occur in other lysosomal diseases.  The life expectancy of females is reduced by about 5 years and for males about 16 years compared with the general US population.

Involvment of the autonomic system manifests as intermittent fever, hypohidrosis, and poor temperature control.  Some patients have periodic crises of severe pain in the extremities as well as intermittent epigastric pain. Hearing loss and episodic tinnitus are common complaints.