Trisomy 9

Overview
Trisomy 9 is a chromosomal disorder caused by having three copies (trisomy) of chromosome number 9. It can appear with or without mosaicism.

Symptoms
Symptoms vary, but usually result in dysmorphisms in the skull, nervous system, and mental retardation. Dysmorphisms in the heart, kidneys, and musculoskeletal system may also occur.

Detection
Trisomy 9 can be detected prenatally with chorionic villus sampling and cordocentesis, and can be suggested by obstetric ultrasonography.

Because trisomy 9 may appear with mosaicism, it is suggested that doctors take samples from multiple tissues when karyotyping for diagnosis.