Fabry Disease p.M290I Mutation is Related to Organ Involvement: A Case Report.

Fabry disease (FD) is an X-linked hereditary disease. It results from mutations in the GLA gene, leading to deficient activity of the enzyme alpha-galactosidase A (α-Gal A) and progressive accumulation of undegraded glycosphingolipids in cell lysosomes. Enzyme replacement therapy (ERT) can improve the natural course of this disease, but an early diagnosis is crucial for a successful treatment. We describe the case of a female diagnosed with chronic proteinuric kidney disease in the postpartum period. Despite receiving optimal medical treatment, the disease progressed and she started renal replacement therapy (RRT) with peritoneal dialysis (PD). Five years later, she was enrolled in a pilot screening study for FD, and the heterozygous mutation c.870G>C (p.Met290Ile; M290I) in exon six of the GLA gene was found. The family screening revealed the presence of this mutation in the patient's father and daughter. The proband did not meet the criteria for a definitive FD diagnosis, but she remained under follow-up at our nephrology metabolic diseases consultation, as the mutation was described as pathogenic and associated with a classic FD phenotype. Later that same year, reassessment exams revealed a worsening left ventricle mass index (LVMi), a new ischemic cerebral lesion, and a substantial increase in serum globotriaosylsphingosine (LysoGb3) levels. These clinical changes led to a decision to initiate ERT. p.M290I is a previously known but poorly described GLA mutation. To our knowledge, this is the first report of p.M290I mutation-associated disease activity that offers strong evidence of its pathogenicity.