Understanding Alkaptonuria

What is Alkaptonuria?

Alkaptonuria (AKU) is a rare genetic disorder that affects how your body breaks down certain amino acids, specifically phenylalanine and tyrosine. This condition is also known as 'black urine disease' due to one of its characteristic symptoms.

Causes

• Inherited genetic mutation in the HGD gene
• Leads to deficiency of homogentisate 1,2-dioxygenase enzyme
• Results in accumulation of homogentisic acid (HGA)

Key Symptoms

Early Signs

• Dark urine that turns black when exposed to air
• Dark staining of diapers in infants
• Brown discoloration of ear cartilage

Later Manifestations

1. Ochronosis (bluish-black pigmentation)
   • Ear cartilage
   • Eye whites
   • Skin
2. Joint Problems
   • Early-onset arthritis
   • Spine stiffness
   • Joint pain

Diagnosis

• Urine examination for HGA
• Genetic testing for HGD gene mutations
• Physical examination for ochronosis

Treatment Options

Current Management

1. Medication
   • Nitisinone (NTBC)
   • Pain management
2. Lifestyle Modifications
   • Low-protein diet
   • Regular exercise
   • Joint protection

Supportive Care

• Physical therapy
• Regular monitoring
• Joint replacement if needed

Living with AKU

• Regular medical check-ups
• Early intervention for complications
• Support group participation
• Genetic counseling for family planning

Prognosis

While there's no cure, early diagnosis and proper management can help control symptoms and prevent complications.