[1] Univ Groningen, Univ Med Ctr Groningen, Dept Surg, Div Pediat Surg, Groningen, Netherlands
[2] Univ Groningen, Univ Med Ctr Groningen, Pediat Gastroenterol & Hepatol, Groningen, Netherlands
[3] Univ Groningen, Univ Med Ctr Groningen, Dept Pathol & Med Biol, Groningen, Netherlands
[4] Univ Groningen, Univ Med Ctr Groningen, Anorectal Physiol Lab, Groningen, Netherlands
[5] Univ Groningen, Univ Med Ctr Groningen, Dept Surg, Div Pediat Surg,Anorectal Physiol Lab, Groningen, Netherlands