Cord Blood

• Confirmation of suspected chromosomal disorder following abnormal antenatal ultrasound undertaken late in pregnancy or where further investigation declined during in the pregnancy.
• Chromosome mosaicism found at CVS, amniocentesis or cordocentesis (where indicated)
• DNA studies. Cord blood confirmation of single gene disorder suspected on ultrasound findings eg achondroplasia
  Testing for late onset disorders should not be undertaken
• Confirmation of biochemistry where prenatal diagnosis of a known condition undertaken (requested by testing lab)

Neonatal Testing

• Blood

1. Clinical features consistent with known chromosomal abnormality.
2. Multiple congenital anomalies consistent with possible chromosomal abnormality
3. FISH; where range of clinical features suggests a specific microdeletion syndrome, specific FISH test should be requested.
4. Ambiguous genitalia.

• Solid Tissues

1. Products of conception.
2. Post mortem - (1) - (4) as above.

Guidelines for DNA Studies in the Neonatal Period

• Features of a single gene disorder/syndrome (for diagnostic purposes) e.g. hypotonia
• Mitochondrial myopathy syndrome.
• Features of possible single gene disorder where infant may die and genetic testing may later become available (DNA storage)