Ngā mate e kitea ana pea i te whakamātau poka rekereke Disorders screened for in the heel prick test (newborn blood spot screening)

All of the screened disorders are rare. They are usually inherited from one or both parents. Your first pēpi (baby) may not have a disorder, but you may have pēpi in the future who are born with a disorder. Different genetic conditions cause each disorder and affect important processes in the body.


About the disorders

Disorders can vary in:

  • when they appear
  • how severe they are
  • how they are inherited.

Without treatment, screened disorders can range from mild to acute life-threatening.


Disorders screened for

Newborn screening tests for the following disorders:

  • congenital hypothyroidism
  • cystic fibrosis
  • amino acid disorders
  • fatty acid oxidation disorders
  • congenital adrenal hyperplasia
  • galactosaemia
  • biotinidase deficiency
  • severe combined immune deficiency
  • spinal muscular atrophy from late 2024 (this will be updated once start date confirmed).

Sometimes new disorders are added to the screening programme, and others are removed.

Why disorders are removed

Disorders are removed where they no longer meet screening criteria, for example, new evidence was assessed by clinical experts and it was agreed that a disorder should no longer be screened. This may be:

  • due to screening for that disorder having insufficient clinical benefit for the child
  • if it was determined that the criteria for screening suitability were not being met due to a high number of false positive results, and lack of true cases detected.

Cause, treatment and frequency of screened disorders

The disorders, cause, treatment, and frequency for Aotearoa New Zealand.

Cause 

The thyroid (a small, butterfly-shaped gland located at the base of the neck, just below the Adam's apple) is missing, formed in the wrong place, or is not working properly and does not produce enough thyroid hormone. This can lead to slow growth and developmental delay.

Treatment

Replacement thyroid hormone medicine.

Frequency

1 in 2,500 pēpi — about 25 a year.

Cause 

A defective gene that makes the body produce abnormally thick and sticky fluid, called mucus. This mucus builds up in the breathing passages of the lungs and in the pancreas, leading to poor absorption of food, poor growth, susceptibility to chest infections and difficulty breathing.

Treatment

Medicine and physiotherapy.

Frequency

1 in 6,000 pēpi — about 10 a year.

Cause 

An enzyme is missing, for example an enzyme (called phenylalanine hydroxylase) in phenylketonuria (PKU). Without this enzyme an amino acid (called phenylalanine) rises to harmful levels and can lead to developmental delay. Other amino acid disorders can lead to serious illness and death.

Treatment

Special diet.

Frequency

1 in 15,000 pēpi — about 4 a year.

Other amino acid disorders

  • argininosuccinic aciduria (argininosuccinate lyase deficiency)
  • citrullinaemia (argininosuccinate synthetase deficiency, citrin deficiency)
  • glutaric acidaemia type I (glutaryl-CoA dehydrogenase deficiency)
  • homocystinuria (cystathionine beta-synthase deficiency)
  • isovaleric acidaemia (isovaleryl-CoA dehydrogenase deficiency)
  • methylmalonic acidurias (mutase deficiency, CblA, CblB, CblC, CblD defects)
  • propionic acidaemia (propionyl-CoA carboxylase deficiency)
  • maple syrup urine disease (branched chain ketoacid dehydrogenase deficiency)
  • tyrosinemia Type I.

Cause

An enzyme needed to break down fats is missing. Without these enzymes energy cannot be converted from fats. This can lead to episodes of low blood sugar, coma and death.

Treatment

Regular feeding, avoid fasting.

Frequency

1 in 10,000 pēpi — about 6 a year.

Other fatty acid disorders

  • CACT (carnitine acylcarnitine translocase deficiency)
  • CPT-I (carnitine palmitoyltransferase-I deficiency)
  • CPT-II (carnitine palmitoyltransferase-II deficiency)
  • LCHAD (3-hydroxy long-chain acyl-CoA dehydrogenase deficiency)
  • TFP (trifunctional protein deficiency)
  • MADD (multiple acyl-CoA dehydrogenase deficiency)
  • MCAD (medium-chain acyl-CoA dehydrogenase deficiency)
  • VLCAD (very-long-chain acyl-CoA dehydrogenase deficiency).

Cause

A missing enzyme in the adrenal gland (glands on top of both kidneys). In severe forms this leads to:

  • A lack of hormone and salt loss that can lead to vomiting, dehydration and life-threatening collapse in the first weeks of life.
  • External genitals that appear masculinized in biological females (ambiguous genitalia)

Treatment

Steriod medicines. 

Frequency

1 in 25,000 pēpi — about 3 a year.

Cause

A defective enzyme prevents normal breakdown and use of milk sugar leading to:

  • yellow skin or eyes (jaundice)
  • blurry vision (cataracts)
  • life threatening illness.

Treatment

Avoiding foods that contain lactose and galactose, such as dairy products.

Frequency

1 in 110,000 pēpi — about 1 every 2 years.

Cause

A missing enzyme resulting in a deficiency in vitamin H (biotin). This deficiency can lead to:

  • seizures
  • hearing loss
  • developmental delay. 

Treatment

Vitamin H (biotins).

Frequency

1 in 180,000 pēpi — about 1 every 3 years.

Cause

A lack of cells essential for immunity can lead to severe and life-threatening infections.

Treatment

Antibiotics, the need for protective isolation and bone marrow transplant.

Frequency

1 in 60,000 pēpi — about 1 a year.