• can develop in children after viral gastroenteritis

  • unusual after bacterial in adults

Symptoms

• colicky abdominal pain

• diarrhoea

• bloating

• hypolatasia compatible with range of symptoms which depend on severity of defect

• more severe malsorpation

  • more rapidly bolus passes

• symptoms only if ≥ 240mL

Pathophys

• Lactase encoded by single gene

• age related inactivation fo noraml gene

• lactaes persistent are either heterozygous or homozygous

• allele found increased frequecny:

  • nortwest europe

• incidence of abnormal lactase persistent phenotype:

  • 90 % northwest europe

  • 60^ mediterranean

  • 40-60% Asia

  • 10% orent

Treatment

• low lactose diet

• Fermented milk products have much reduced lactose content

  • e.g. yoghurt better tolerated

• commercial supplements can be added