X Linked Hypophosphatemia

From Anvita Health Wiki

Contents 1 Epidemiology 2 Pathology 3 Genetics 4 Clinical-manifestations 5 Laboratory 6 Management 7 More General Terms 8 Additional Terms 9 Internet Database 10 References

Epidemiology

• bony abnormalities are less common in women

Pathology

• reduced proximal tubular resorption of phosphate
• increased fractional excretion of phosphate
• osteomalacia develops in adult life
• overgrowth of bones at sites of muscular tendon attachment may compress nerves or limit movement

Genetics

• X-linked inheritance

Clinical-manifestations

• patients may be asymptomatic
• short stature, rachitic bones
• legs are particularly short & deformed
• bone age & dentition are retarded
• skull becomes deformed

• maxillofacial region may be abnormal

Laboratory

• serum chemistries

• hypophosphatemia
• alkaline phosphatase is elevated
• parathyroid hormone ( PTH) is normal or high
• Ca+2 is normal

• urine chemistries

• Ca+2 excretion is normal or low
• mild glycinuria & glycosuria may occur

Management

• phosphate ( NutraPhos) 1-4 g/day in divided doses
• calcitriol or some other form of vitamin D
• orthopedic management

• delay corrective surgery until active growth phase is complete (exception is genu valgum { knock knee})

More General Terms

• genetic disease of bone/skeletal system
• metabolic disease

Additional Terms

• hypophosphatemia

Internet Database

OMIM: 307800

References

Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 1328

X-linked hypophosphatemia