There are a number of reasons for genetic testing in children. These include a specific syndromes, developmental delay, autism, mental retardation, delayed puberty and growth.
Specific testing may be needed for newborn infants who have features of a specific clinical syndrome, have ambiguous genitalia or for confirmation of an abnormality found at prenatal diagnosis.
There are 3 methods of testing:
- Conventional banded karyotype – for sex chromosomes disorders, unbalanced chromosome rearrangements, balanced chromosome rearrangements or investigation of low grade mosaicism
- Microarray – this detects gain or loss of genetic material that is smaller than that which can be detected by a banded karyotype and covers all chromosomes. It cannot detect balanced rearrangements. It is the best test for children with intellectual disabilities and congenital anomalies (with a Medicare rebate for this indication).
- FISH is used for microdeletion syndromes and is a rapid method of testing.