Partial trisomy of the long arm of chromosome 9 represents a very rare and heterogeneous group of chromosomal aberrations. Associated clinical features include learning disability and pyloric stenosis. We present the first patient to be reported with a duplication of the chromosome region 9q22.1→q33. The patient (female, age 17 years) presented with growth retardation, microcephaly, facial dysmorphia, oesophageal atresia, aortic stenosis, ventricular septal defect, atrial septal defect II, hypothyroidism, and learning disability, but no pyloric stenosis. A review of all cases of partial trisomy 9q reported in the literature demonstrates that learning disability is a characteristic feature of this group of chromosomal aberrations. However, there are cases of duplications of the same chromosome 9 material, with and without pyloric stenosis. This study provides new information for future genetic counselling, especially in cases of prenatal diagnosis of partial trisomy 9q.