Deciphering the diagnostic dilemma: A comprehensive review of the Taiwanese cardiac variant in Fabry disease.

Molecular diagnosis has undergone rapid and significant advancements in recent years. But because molecular diagnosis can be conducted independently of phenotype, it can engender ambiguity and potential misinterpretations in disease diagnosis. Fabry disease, an X-linked lysosomal storage disorder, arises from a deficiency in α-galactosidase A. In 2002, Ishii and colleagues uncovered a variant (IVS4+919G > A) deep within intron 4 of the GLA gene that could lead to aberrant splicing of the GLA mRNA. This variant is present in 1:875 males in Taiwan, and many patients with hypertrophic cardiomyopathy and the IVS4+919G > A variant are currently treated by enzyme replacement therapy, an expensive treatment. Unfortunately, till now only one article published in 2013 described the outcome of treatment. This review summarized the conflicting evidence about the clinical relevance of the IVS4+919G > A variant, and suggest a multifactorial model, rather than a monogenic model, for the involvement of the IVS4+919G > A variant in hypertrophic cardiomyopathy. The diagnostic dilemma for this Taiwanese cardiac variant in Fabry disease clearly emphasizes the need for precise interpretation and application of molecular diagnostic results.