Late gadolinium enhancement shows increased signal of the midwall at the inferolateral wall of the base of the left ventricle, usually in the non-hypertrophic ventricle. T1-weighted imaging can show low T1 signal due to sphingolipid storage in the heart even without ventricular hypertrophy in 40% of the those affected by the disease. Thus, MRI is a useful way of diagnosing the disease early. T2 signal is increased in inflammation and oedema. Treatment
The treatments available for Fabry disease can be divided into therapies that aim to correct the underlying problem of decreased activity of the alpha galactosidase A enzyme and thereby reduce the risk of organ damage, and therapies to improve symptoms and life expectancy once organ damage has already occurred. Therapies targeting enzyme activity
Enzyme replacement therapy is designed to provide the enzyme the patient is missing as a result of a genetic malfunction. This treatment is not a cure, but can partially prevent disease progression, and potentially reverse some symptoms. As of March 2022, two medical drugs based on enzyme replacement therapy are available for Fabry disease:
Agalsidase alfa, sold under the brand name Replagal by the company Takeda (since its acquisition of the company Shire), is a recombinant form of alpha-galactosidase A It received approval in the EU in 2001. FDA approval was applied for the United States. However, Shire withdrew their application for approval in the United States in 2012, citing that the agency will require additional clinical trials before approval. As of March 2022, Replagal has not received FDA approval.
Enalaprilat is the active metabolite of enalapril. It is the first dicarboxylate-containing ACE inhibitor and was developed partly to overcome these limitations of captopril. The thiol functional group of captopril was replaced with a carboxylic acid group, but additional modifications were required to achieve a potency similar to captopril. Enalaprilat, however, had a problem of its own. The consequence of the structural modifications was that its ionisation characteristics do not allow for sufficient GI absorption. Thus, enalaprilat was only suitable for intravenous administration. This was overcome by the monoesterification of enalaprilat with ethanol to produce enalapril. As a prodrug, enalapril is hydrolyzed in vivo to the active form enalaprilat by various esterases. Peak plasma enalaprilat concentrations occur 2 to 4 hours after oral enalapril administration. Elimination thereafter is biphasic, with an initial phase which reflects renal filtration (elimination half-life 2 to 6 hours) and a subsequent prolonged phase (elimination half-life 36 hours), the latter representing equilibration of drug from tissue distribution sites. The prolonged phase does not contribute to drug accumulation on repeated administration but is thought to be of pharmacological significance in mediating drug effects. Renal impairment [particularly creatinine clearance < 20 ml/min (< 1.2 L/h)] results in significant accumulation of enalaprilat and necessitates dosage reduction. Accumulation is probably the cause of reduced elimination in healthy elderly individuals and in patients with concomitant diabetes, hypertension and heart failure. == References ==