A new patient with trisomy for the chromosome segment 9pter----q22 is compared to 19 previously reported cases of partial trisomy 9. Manifestations such as microcephaly, prominent nasal root, bulbous nose, and down-turned corners of the mouth are common to patients with trisomic segments extending from 9p21 to 9q13, while intra-uterine growth retardation, cleft lip/palate, skeletal anomalies, and heart defects are more common with trisomic segments extending through 9q22-9q32. A graphic method illustrates this progression in the partial trisomy 9 malformation spectrum as the triplicated chromosome region extends from bands 9p21 to 9q32. More severe and random defects are observed with complete trisomy 9 or tetrasomy 9p, suggesting an extreme excess of material greatly increases developmental variability.
Karyotypes were examined in 122 Omani children suspected of having chromosomal abnormalities. A total of 50 (41 per cent) had an abnormal karyotype: 38 (31 per cent) were Down's syndrome whilst a further 12 (10 per cent) had other types of chromosomal abnormalities. These findings suggest that cytogenetic analysis is useful in the investigations of children with congenital anomalies of unknown origin; to confirm clinical diagnosis in children with known cytogenetic syndromes and for genetic counselling.
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