Late-Onset Pyloric Stenosis and Intussusception With Final Diagnosis of Food Proteins' Hypersensitivity in Schaaf-Yang Syndrome: A Case Report.

Schaaf-Yang syndrome (SYS) is a rare neurodevelopmental disorder whose clinical spectrum includes neurodevelopment delay, dysmorphic features, and gastrointestinal symptoms such as feeding difficulties, gastroesophageal reflux, and chronic constipation. Given the small number of patients diagnosed with this syndrome, our aim is to describe novel clinical features that have not yet been reported. The patient we are describing is a 14-year-old male affected by a severe form of SYS. Initial clinical presentation included respiratory distress at birth, feeding difficulties, and neurodevelopmental delay. Since the age of 8 months, he had been tube fed with a semi-elemental formula, and this was well tolerated. At 9 years of age, the pathological mutation (variant in gene) associated with SYS was diagnosed. At 13 years of age, he presented severe gastrointestinal symptoms associated to progressive feeding difficulties. He also suffered from recurrent pancreatitis, late-onset pyloric stenosis and intussusception. Histology showed duodenal villous atrophy with a negative serology for celiac disease. Food protein's hypersensitivity was diagnosed and symptoms resolved after starting an elemental formula.