Genomics in general practice


Newborn screening
☰ Table of contents


Practice point


Screening is available to all newborns in Australia free of charge, and almost all babies are screened. There are some babies who may be lost to follow up or their parents may refuse consent for screening. Exact numbers in Australia are not available. Depending on the condition, not all affected babies will be identified (eg only the most common variants causing cystic fibrosis [CF] are included in the screening test). Therefore, any suggestive symptoms in a child warrant further investigation by the general practitioner (GP).

Depending on the program, GPs may or may not be notified of a positive screening result. Follow-up is usually handled by the screening program.

 


What do I need to know?


Screening can identify a number of rare but serious medical conditions, where early detection and intervention can save lives or provide other benefits to the newborn.

Traditionally, conditions included in the program are based on the ability of clinicians to intervene early to avoid death, disability or other harm. With the advancement of genetic technology, there is some interest in expanding newborn screening panels to include a wider range of conditions.1–3
Newborn screening is optional in Australia,1 and research suggests participation is very high.4 Screening occurs two to  three days after birth, and is usually arranged by midwives. In general, parents are not contacted when screening results are normal.

About 1–2% of babies tested require repeat or subsequent diagnostic testing. Screening programs in each state and territory are usually responsible for following up cases that require further testing. About one per 1000 (0.1%) babies tested will be diagnosed with a condition because of newborn screening.

Refer to Table 1 for a list of conditions currently included in newborn screening programs in Australasia.

 

Table 1. Conditions screened in newborn screening programs in Australasia1,3

Class

Condition

Amino acids

Argininaemia or arginase deficiency

 

Argininosuccinic aciduria

 

Citrullinaemia

 

Tyrosinaemia type 1

 

Homocystinuria

 

Maple syrup urine disease

 

Phenylketonuria

 

Pterin defects

 

Tyrosine aminotransferase deficiency

Organic acids

Beta-ketothiolase deficiency

 

Cobalamin C defect

 

Glutaric acidaemia type I

 

Holocarboxylase synthetase deficiency

 

3-hydroxy-3-methylglutaryl-CoA lyase (HMGCoA lyase) deficiency

 

Isobutyryl-CoA dehydrogenase deficiency

 

Isovaleric acidaemia

 

Methylmalonic acidurias

 

Propionic acidaemia

 

3-methylcrotonyl-CoA carboxylase deficiency

 

2-methylbutyryl-CoA dehydrogenase deficiency

 

3-methylglutaconyl-CoA hydratase deficiency

Fatty acid oxidation

Carnitine or acylcarnitine translocase deficiency

 

Carnitine transporter defect

 

Carnitine palmitoyl transferase deficiency types I and II (CPTI)

 

3-hydroxy long chain acyl-CoA dehydrogenase deficiency (LCHAD)

 

Medium chain acyl-CoA dehydrogenase deficiency (MCAD)

 

Multiple acyl-CoA dehydrogenase deficiency (MADD)

 

Short chain acyl-CoA dehydrogenase deficiency (SCAD)

 

Short chain hydroxy acyl-CoA dehydrogenase deficiency (SCHAD)

 

Trifunctional protein deficiency (TFP)

 

Very long chain acyl-CoA dehydrogenase deficiency (VLCAD)

Other

Cystic fibrosis (CF)

 

Congenital hypothyroidism

 

Galactosaemia (not in Victoria)

 


Other considerations


In addition to the implications for a child diagnosed with an inherited condition, there are also implications for future pregnancies in the family (ie carrier parents, siblings of the carrier parents). Information about carrier screening should be offered.


Genomics in general practice




 

 

  1. Human Genetics Society of Australasia. Policy: Newborn bloodspot testing. Sydney: HGSA, 2011. [Accessed 8 January 2018].
  2. Howard HC, Knoppers BM, Cornel MC, et al. Whole-genome sequencing in newborn screening? A statement on the continued importance of targeted approaches in newborn screening programmes. Eur J Hum Genet 2015;23(12):1593–600.
  3. Wilcken B, Wiley V. Newborn screening. Pathology 2008;40(2):104–15.
  4. Jacques AM, Collins VR, Pitt J, Halliday JL. Coverage of the Victorian newborn screening programme in 2003: A retrospective population study. J Paed Child Health 2008;44(9):498–503.
 
 

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