Clinical and radiographic examinations and MR scan of a 12-year-old girl with SMMCI (single median maxillary central incisor) showed impaired growth and a midline defect involving the central incisor, cranium and the midline structures in the brain, falx cerebri and pituitary gland. She had a severe growth hormone deficiency but no other pituitary hormone deficiencies. She was treated with growth hormone and followed during a four-year period with successful gain in body height and sexual maturation. This study focuses on the developmental association between the involved structures and provides guidelines for early diagnostics.