Complex sentence: Classic symptoms include gastrointestinal problems such as chronic diarrhoea, abdominal distention, malabsorption, lose of appetite, and failure to thrive (in children), is the least common presentation of the disease and affects predominantly children younger than two years of age.
Split into simpler sentences: Classic symptoms include gastrointestinal problems such as chronic diarrhoea, abdominal distention, malabsorption, lose of appetite, and failure to thrive (in children). This is a less common presentation of the disease and more often affects children younger than two years of age.