Rare metabolic conditions

 

  1. Newborn screening also includes a screen for over 20 additional rare metabolic conditions using mass
    spectrometry.
  2. See list of ‘Rare metabolic conditions that are recommended in Australian newborn screening programmes’ that may be included.
  3. Most of these metabolic conditions follow a pattern of autosomal recessive inheritance.
  4. In some cases the baby may present in crisis prior to diagnosis by newborn screening.
  5. Three groups of conditions can be detected: disorders of fatty acid oxidation, organic acidaemias, and
    other acidopathies.
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Disorders of fatty acid oxidation

  1. Defects in the ‘burning’ of fatty acids.
  2. The most common condition is medium chain acyl-coA dehydrogenase (MCAD) deficiency:
  3. Can be life threatening
  4. Children with this condition are usually well but may suffer metabolic decompensation if fasting
  5. May present with lethargy and coma, or hypoglycaemic seizure, during intercurrent illness
  6. Management consists of avoiding fasting and taking special measures when the child has an
    intercurrent infection
  7. Newborn siblings of known cases are at high risk in the first 3 to 4 days of life, and should be monitored and offered 3-hourly feeds
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Organic acidaemias/acidurias

  1. These conditions result from defects in metabolism of, most commonly, amino acids.
  2. These conditions are rare but can be life threatening.
  3. Some of these conditions require treatment with a low-protein diet, supplements and medications.
  4. Early treatment is associated with reduced mortality and morbidity.
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