This karyotype shows an extra copy of chromosome 18, which is associated with a clinical diagnosis of trisomy 18. Trisomy 18 is characterized by multiple congenital abnormalities and developmental delay.
This karyotype shows a balanced translocation between the long arms of chromosomes 7 and 18. Balanced translocations are not typically associated with multiple congenital abnormalities and dysmorphic features unless: (1) there is an accompanying submicroscopic microdeletion/microduplication at the breakpoint regions, or (2) the breakpoint occurs in a critical region with concomitant disruption of the gene function.
This karyotype shows an extra copy of chromosome 16 (trisomy 16), which is always lethal in the first or second trimester.
This karyotype shows an extra copy of the X chromosome, which is associated with a clinical diagnosis of the triple X syndrome. Physical development in females with XXX is generally unremarkable and there are no phenotypic abnormalities. Some may be tall, be at risk for learning disabilities, and may have fertility problems. There is a general tendency for IQ to be slightly reduced, compared with siblings.
This karyotype shows a balanced pericentric inversion of chromosome 9. Most pericentric inversions confer an increased risk for miscarriages and offspring with congenital abnormalities and/or mental retardation as a result of unbalanced segregation during gametogenesis. However, this particular inversion is a well-established benign polymorphism with no associated clinical risks.
