MTP-101P

The investigators propose to investigate Microbiota Transfer Therapy (MTT) for treating patients with Pitt-Hopkins Syndrome (PTHS) and gastrointestinal problems (constipation, bloating, abdominal pain). MTT involves a combination of 10 days of oral vancomycin (an antibiotic to kill pathogenic bacteria), followed by 1 day of bowel cleanse using magnesium citrate, followed by 4 days of high dose MTP-101P with an antacid, followed by 12 weeks of a lower maintenance dose of MTP-101P with an antacid.