One female with CBE in combination with duodenal stenosis carried a 375 kb duplication on chromosome Xq28 containing only a few genes: Small integral membrane protein 9 (SMIM9), Coagulation factor VIII (F8), FUN14 Domain Containing protein 2 (FUNDC2), and C‐X9‐C Motif containing 4 (CMC4), Mature T‐cell proliferation 1 (MTCP1), and the BRCA1/BRCA2‐containing complex, subunit 3 (BRCC3). The gene discussed is CMC4; the disease is Duodenal stenosis.