Trisomy 9 syndrome: report of a case with Crohn disease and review of the literature.

We report on a 6-year-old boy with mosaic trisomy 9. The patient was born at 42 weeks of gestation to a 27-year-old G1 white woman. Birth weight was 2,820 g, length 52 cm, and Apgar scores were 4 and 6 at 1 and 5 min, respectively. The infant presented with apparently low-set ears, overfolded helices, epicanthal folds, prominent nasal bridge, high-arched palate, micrognathia, bilateral dislocated hips, left genu recurvatum, and cryptorchidism. Chromosome analysis showed an unusual karyotype: 47,XY,+inv(9qh+)/47,XY,+mar. The marker chromosome was thought to be a remnant of the inv(9qh+) chromosome. The mother's karyotype was 46,XX,inv(9qh+), while the father's was 46,XY. At age 5 months, the patient developed seizures and gastroesophageal reflux. Crohn disease was diagnosed at age 2 years, although symptoms began at age 1 year. Recurrent bouts of pneumonia have occurred since the patient's birth. Severe psychomotor retardation was also noted. Trisomy 9 syndrome was first reported in 1973. Over 30 cases have been reported since then. Of these cases reports, only 5 patients were older than 1 year. Inflammatory bowel disease has been reported in association with other chromosome abnormalities, but to our knowledge, has not been reported in trisomy 9 syndrome.