Selected inherited disorders
Various inherited disorders are summarized in Table 81.1.
Table 81.1
| Disorder | Main feature |
| Acute intermittent porphyria | The porphyrias are disorders of haem biosynthesis. The acute porphyrias which present with abdominal pain and neurological features all have increased urinary porphobilinogen during an attack, and this is diagnostic |
| Adrenoleucodystrophy | This rare neurodegenerative disease is characterized by the impaired metabolism and subsequent accumulation of long chain fatty acids in plasma and tissues, and adrenal insufficiency |
| Agammaglobulinaemia | There is a complete absence of immunoglobulin production. Selective IgA deficiency is more common with affected children presenting with recurrent respiratory infections |
| Alpha-1-antitrypsin deficiency | Patients with deficiency of the protease inhibitor, alpha-1-antitrypsin, may present with liver disease in childhood or with pulmonary emphysema in adults. All patients with genotypes associated with low alpha-1-antitrypsin in the serum are likely to develop emphysema if they smoke or are exposed to environmental pollutants |
| Biotinidase deficiency | A failure of biotin recycling results in an organic aciduria, developmental delay, seizures, alopecia, hypotonia and hearing loss |
| Congenital adrenal hyperplasia | This name is given to disorders of the enzymes involved in steroid hormone biosynthesis. The most common is lack of the 21-hydroxylase on the pathways which lead to cortisol and aldosterone synthesis (pp. 94–95) |
| Cystic fibrosis |
