Hurler syndrome

• Disease Description (Causes and Symptoms)

  • Definition and Causes
    • Hemophilia is a congenital bleeding disorder caused by a deficiency of blood coagulation factors. The main types are
      • Hemophilia A: deficiency of coagulation factor VIII (F8 gene) — X-linked recessive
      • Hemophilia B: deficiency of factor IX (F9 gene, Christmas disease) — X-linked recessive
      • Hemophilia C: deficiency of factor XI — autosomal recessive (rarely reported)
    • Symptoms occur predominantly in males, while females are often carriers.
  • Pathophysiology
    • The intrinsic coagulation pathway is impaired by the deficient coagulation factor, resulting in delayed bleeding and a tendency toward persistent bleeding.
  • Main Symptoms
    • Severe disease: spontaneous bleeding (subcutaneous bleeding, intramuscular bleeding, hemarthrosis), recurrent joint bleeding in children → arthritic deformity
    • Persistent bleeding after trauma, surgery, or tooth extraction
    • In severe cases, life-threatening bleeding such as intracranial hemorrhage may occur
  • Test Findings (Screening)
    • Normal platelet count, bleeding time, and PT; prolonged PTT (partial thromboplastin time), particularly evident in moderate to severe disease
    • Definitive diagnosis: blood coagulation factor activity testing (factors VIII, IX, etc.) and genetic testing (identification of F8 and F9 mutations)

• Treatment Methods and Precautions

  • Treatment of Acute Bleeding
    • Replacement of the deficient factor is the principle of treatment: concentrated factor preparations (recombinant or plasma-derived factor VIII/IX concentrate)
    • If concentrates cannot be used in an emergency, fresh frozen plasma (FFP) or cryoprecipitate (mainly related to factor VIII)
    • In cases of severe bleeding or surgery, dosing and repeated administration according to the target factor activity (%) are necessary
    • Pain relief should be prioritized after factor replacement; NSAIDs (ibuprofen, indomethacin, etc.) and aspirin-based drugs are contraindicated due to the risk of bleeding → acetaminophen is preferred
  • Preventive (Prophylactic) Treatment
    • Regular factor replacement to prevent spontaneous bleeding and joint destruction (particularly recommended for patients with severe disease)
    • Early treatment and cost reduction may be possible through intravenous infusions at home (self-administration or administration by a trained caregiver)
  • Management When Antibodies (Inhibitors) Develop
    • When high-titer antibodies develop, the effect of standard factor replacement decreases → use activated prothrombin complex concentrate (aPCC) or recombinant activated factor VII (rFVIIa) as alternative therapies; long-term induction of immune tolerance (ITI) may be considered
  • Other Treatment and Management
    • Orthopedic management: arthropathy caused by recurrent joint bleeding requires rehabilitation, physical therapy, and, if necessary, surgery
    • Genetic counseling, carrier testing, and prenatal testing are available
    • Latest treatment: gene therapy (clinical trials and some approved treatments exist) — consultation with a specialist is necessary regarding indications, risks, durability, and other factors
  • Summary of Prevention and Precautions
    • Factor replacement in advance when necessary for invasive procedures (injections, blood sampling, treatment)
    • Avoid intramuscular injections (risk of bleeding and hematoma); administer by intravenous injection
    • In an emergency, present the medical staff with a history of hemophilia and records of factor preparation administration (a medical alert bracelet is recommended)
    • Although the risk of infection related to vaccines and blood products is lower than in the past, confirm the medical history and follow standard precautions

• Checkpoints Before an Outpatient Visit (Including Items to Bring and Example Questions)

  • Items to Bring (for an outpatient visit)
    • List of all currently used medications and supplements
    • Past bleeding diary (when, site, and treatment details), and records of regular administration (prophylaxis)
    • Previous blood test results (PTT, factor activity, inhibitor testing, etc.) and genetic test results (if available)
    • Treatment or procedure plans if surgery or dental treatment is scheduled
    • History of vaccinations, hepatitis testing, and HIV testing (such as for previous blood transfusion recipients)
  • Information to Tell the Doctor During the Outpatient Visit
    • Recent bleeding frequency, site, and severity, and whether trauma occurred
    • History of factor administration at home and adverse effects (fever, allergic reactions, etc.)
    • Family history (whether there is hemophilia or carrier status)
  • Example Questions (for patients and caregivers to check themselves before the appointment)
    • How frequent has the recent bleeding been?
    • What is the usual factor replacement schedule and the most recent dose?
    • Is surgery or a dental procedure planned?

• Examples of General Questions to Ask the Doctor

  • What are the expected side effects of this treatment (factor replacement therapy)?
  • How often should inhibitor testing be performed?
  • How are the timing and frequency of starting prophylaxis determined?
  • What should I be careful about in daily life (exercise, career choice, childbirth, etc.)?
  • How does the prognosis differ according to the degree of factor deficiency?

• Examples of Disease-Specific Questions

  • (Related to hemophilia A) Am I (or is my caregiver) a candidate for DDAVP (desmopressin) treatment? What are its effects and side effects?
  • (Related to hemophilia B) Could you explain whether I meet the indications for gene therapy (e.g., Hemgenix), as well as its short- and long-term effects and risks?
  • (For a carrier or a woman planning pregnancy) What are the timing and procedures for carrier testing and prenatal diagnosis (chorionic villus sampling and amniocentesis)?

(Note: The selection of tests and treatments varies according to the individual patient's condition (severity, presence of inhibitors, comorbidities, etc.). Please consult a specialist to determine a specific diagnosis and treatment plan.)