The demonstration of marked alpha-galactosidase deficiency is the conclusive method for the diagnosis in homozygous males. It may be detected in heterozygotous females, but it is often inconclusive due to random X-chromosomal inactivation, so molecular testing (genotyping) of females is mandatory. Diagnosis
Fabry disease is suspected based on the individuals clinical presentation, and can be diagnosed by an enzyme assay (usually done on leukocytes) to measure the level of alpha-galactosidase activity. An enzyme assay is not reliable for the diagnosis of disease in females due to the random nature of X-inactivation. Molecular genetic analysis of the GLA gene is the most accurate method of diagnosis in females, particularly if the mutations have already been identified in male family members. Many disease-causing mutations have been noted. Kidney biopsy may also be suggestive of Fabry disease if excessive lipid buildup is noted. Pediatricians, as well as internists, commonly misdiagnose Fabry disease. All immediate and extended family members in the same family have the same family mutation, so if one member of a family has a DNA sequence analysis performed, other members of the family can be diagnosed by performing a targeted sequence analysis instead of testing the entire gene. Targeted sequencing is quicker and less expensive to perform. One study reported that for every first diagnosis in a family, on average five more family members (immediate and extended) are also diagnosed.MRI is accurate in accessing left ventricular mass and thickness and hypertrophy.
This accumulation leads to an impairment of their proper functions.At least 443 disease-causing mutations in the GLA gene have been discovered. The DNA mutations that cause the disease are X-linked recessive with incomplete penetrance in heterozygous females. The condition affects hemizygous males (i.e. all non-intersex males), as well as homozygous, and in many cases heterozygous females. While males typically experience severe symptoms, women can range from being asymptomatic to having severe symptoms. Research suggests many women experience severe symptoms ranging from early cataracts or strokes to hypertrophic left ventricular heart problems and kidney failure. This variability is thought to be due to X-inactivation patterns during embryonic development of the female. Mechanism
Fabry disease is an inherited lysosomal storage disorder that is caused by a deficiency of alpha-galactosidase A. This enzyme deficiency is a result of an accumulation of glycosphingolipids found in the lysosomes and most cell types and tissues, which leads it to be considered a multisystem disease. Indications include painful crisis, angiokeratomas, corneal dystrophy, and hypohydrosis. In severe cases there is renal, cerebrovascular, and cardiac involvement and it is predominately responsible for premature mortality in Fabry patients. Fabry disease is X-linked and manifests mostly in homozygous males but also in heterozygous females. Cardiac involvement is recurrent in Fabry patients. Patients have developed hypertrophic cardiomyopathy, arrhythmias, conduction abnormalities, and valvular abnormalities. Deficient activity of lysosomal alpha-galactosidase results in progressive accumulation of globotriaosylceramide (GL-3) within lysosomes, that is believed to trigger a cascade of cellular events.