Current Pharmaceutical Design - Volume 19, Issue 33, 2013

Anderson-Fabry disease is an X-linked lysosomal storage disorder caused by a defect in the α-galactosidase A gene, which leads to the deficiency of the hydrolytic enzyme α-galactosidase A. The consequent inability to catabolize glycosphingolipids causes progressive accumulation of globotriaosylceramide in the vascular endothelium throughout the body. Fatalities in the classical phenotype may usually occur as a consequence of cerebral, cardiac or renal disease. Dermatological manifestations are a relevant feature of Fabry disease and include angiokeratomas, telangiectasiae, lymphedema, anhidrosis or hypohidrosis and pseudo-acromegalic facial appearance. The actual causal treatment for Fabry disease is the enzyme replacement therapy. Dermatologists have a key role, since cutaneous manifestations may lead to the diagnosis. This may help an early therapeutic intervention, reducing both morbidity and mortality.

Although clinical evidence of major organ damage is typical of adulthood, many of the signs and symptoms of Anderson Fabry Disease (AFD) occur frequently in childhood. The clinical phenotype of AFD in pediatric patients has been described in several studies which show a higher incidence and an earlier onset of symptoms in male patients than in females. These include neurological manifestations (acroparaesthesias, chronic neuropathic pain, hypo-anhidrosis, tinnitus, hearing, loss), gastrointestinal (GI) symptoms (abdominal pain and diarrhea), angiokeratomas, ocular abnormalities (cornea verticillata, tortuous retinal vessels and subcapsular cataracts). Such manifestations may impair quality of life and, because of their unspecific nature, rarely lead to an early diagnosis. In addition, signs of major organ damage (microalbuminuria or proteinuria, urinary hyperfiltration, impaired heart rate variability, left ventricular hypertrophy, stroke) are encountered in children with AFD. Clinical trials of enzyme replacement therapy (ERT) with agalsidase alfa and agalsidase beta have been conducted in children, with clinical and pharmacodinamc effects proved by both enzyme formulations, whereas differences in safety profile and administration were found. Although several studies suggest that ERT should be started before irreversible damage in critical organs have occurred, the issue of when to initiate it has not yet been resolved. More controlled trials must be done in order to demonstrate that an early start of ERT could prevent adult complications and to assess the optimal timing of treatment in children with AFD. This review aims to provide an update of the current understanding for a better approach of pediatric AFD.

Fabry disease is a progressive devastating disease caused by absent or deficient activity of lysosomal enzyme alphagalactosidase A, with progressive accumulation of globotriaosylceramide (GL-3) within lysosomes in a different cell types. Accumulation of GL-3 and related glycosphingolipids in different cell types may create diverse clinical picture depending on the organ which is dominantly affected. Renal pathology progresses in severity with aging. Globotryaosil ceramide deposits may be found in different cell types within the kidney. Deposition within the glomeruli may be found in endothelial cells, mesangial cells, interstitial cells, with the highest level found within the podocytes. Although Fabry disease is not curable at the moment, availability of enzyme replacement therapy made it possible to treat this group of patients. Two formulations of recombinant human alpha-galactosidase A are present on the market: agalsidase alfa and agalsidase beta. Longer follow-up period is necessary to estimate the impact of ERT on mortality. Patients with end-stage renal disease caused by Fabry disease could be safely treated with enzyme replacement therapy regardless of the method of renal replacement therapy.