Fabry disease

Disease Description (Causes and Symptoms)

• Definition and pathophysiology: This is an X-linked recessive lysosomal storage disease in which mutations in the GLA gene cause deficient or reduced activity of the α-galactosidase A (α‑GAL) enzyme, resulting in the accumulation of globotriaosylceramide (Gb3) in lysosomes. Accumulation in the vascular endothelium and small blood vessels causes microvascular ischemia and organ damage. Female carriers may have variable symptoms depending on the X-chromosome inactivation pattern.
• Main symptoms
  • Childhood and adolescence: Burning pain in the hands and feet (peripheral neuropathic pain), acute pain attacks (Fabry crises), reduced sweating (anhidrosis), angiokeratomas (dark red skin rashes), corneal opacity (observed without reduced vision), gastrointestinal symptoms (abdominal pain and diarrhea)
  • Adult complications: Kidney damage (proteinuria → chronic renal failure), heart disease (left ventricular hypertrophy, myocardial fibrosis, arrhythmia, coronary ischemia), cerebrovascular disease (ischemic stroke at a young age), respiratory and other organ dysfunction
  • Female carriers: Usually mild or asymptomatic, but some may show a typical presentation or severe manifestations limited to specific organs
• Epidemiology (reference): Rare; although estimates vary by report, approximately 1 in tens of thousands to hundreds of thousands of people (listed in the provided information as approximately 1 in 120,000 people).

Treatment Methods

• Disease-modifying treatment
  • Enzyme replacement therapy (ERT): Replaces deficient α‑GAL through regular intravenous infusions. Representative agents include agalsidase alfa (e.g., Replagal) and agalsidase beta (e.g., Fabrazyme). (Dosage and administration differ by product; follow the treating physician’s instructions and pharmaceutical guidance.)
  • Pharmacological chaperone therapy: migalastat (oral) — effective only for specific (“amenable”) GLA variants. Whether a variant is amenable is determined based on genetic analysis results.
  • Gene therapy and new drug development: Multiple gene therapies and substrate reduction therapies (SRTs) are under investigation, but standard treatment remains ERT and migalastat.
• Symptomatic treatment and organ-specific management
  • Pain: Neuropathic pain medications such as gabapentin/pregabalin, tricyclic antidepressants, or SNRIs (e.g., duloxetine); short-term opioids may be considered for severe pain. Avoid temperature extremes, overexertion, and stress.
  • Kidneys: Control proteinuria with ACE inhibitors/ARBs, follow a low-salt and low-protein diet, and consider dialysis or kidney transplantation if the disease progresses.
  • Heart: Standard heart failure treatment (ACEi/ARBs, beta-blockers, diuretics, etc.); catheter ablation, a pacemaker, or an ICD may be considered for arrhythmias; standard treatment is used for coronary artery disease.
  • Cerebrovascular disease: Prevention and treatment of stroke (antiplatelet agents/anticoagulants when indicated), following acute stroke protocols.
  • Skin lesions: Angiokeratomas may be treated with laser therapy for cosmetic or symptomatic purposes.
• Lifestyle management and precautions
  • Avoid factors that trigger pain (high temperatures, strenuous exercise, stress, and dehydration).
  • Have regular follow-up examinations of the kidneys, heart, and neurological system (see Monitoring below).
  • Because this is a familial disease, genetic counseling and family screening are recommended.
  • Consult a specialist regarding pregnancy, breastfeeding, and concomitant medications. The indication for migalastat is limited depending on the variant, and its use during pregnancy or breastfeeding may not be recommended (individual consultation is required).

Checklist Before an Outpatient Visit (Items to Bring and Example Questions)

• Items to bring (recommended)
  • A list of all medications and supplements currently being taken (including dosage/frequency)
  • Previous test results (genetic testing, α‑GAL enzyme activity testing, urinalysis, blood tests, kidney function tests, ECG, echocardiography, cardiac MRI, brain MRI, etc.)
  • Records of pain and symptoms (when they occur, severity, triggers, duration), and photographs of attacks (such as skin lesions)
  • Family history information (similar symptoms, kidney failure, heart disease, or stroke at a young age, etc.)
  • Pregnancy plans or breastfeeding status (if applicable)
• Key information to tell the doctor in advance during the outpatient visit
  • Whether there have been recent changes in proteinuria or kidney function
  • A history of arrhythmia, fainting, or stroke at a young age
  • Whether ERT or migalastat was previously administered and any experience of adverse effects
  • The nature of the pain and factors that worsen it

General Example Questions to Ask the Doctor

• “Based on my test results, what treatment options are recommended in my case? Which is more suitable, ERT or migalastat?”
• “If I start enzyme replacement therapy (ERT), what benefits and adverse effects can I expect?”
• “What tests should I have, and how often should I be monitored, to reduce my risks of kidney disease, heart disease, and stroke?”
• “Which medication should I try first for pain control, and how can its adverse effects be managed?”
• “What genetic testing and counseling do you recommend for my family members (siblings, children, etc.)?”
• “I am planning a pregnancy. Do I need to stop treatment (ERT or migalastat)? What is known about its safety?”

Examples of Disease-Specific Questions

• “Could you confirm whether migalastat treatment is appropriate based on my GLA genetic test result (variant name: ______)?”
• “My current proteinuria (e.g., 24-hour protein amount/urine protein test value) is ____. When should I start ERT for the greatest kidney-protective effect?”

(Additional recommendation) Diagnosis and treatment decisions should be discussed with a specialist (medical genetics, nephrology, cardiology, etc.) based on a comprehensive assessment of genetic testing, enzyme testing, and clinical findings.