A patient has a 2-year-old son with chronic pulmonary disease. His recent sweat test showed an elevated chloride level.
- Autosomal dominant
2) Autosomal recessive
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is X-linked recessive and is found predominantly in males of African and Mediterranean origin. Although the causes of clinical manifestations in G6PD deficiency are multifactorial (eg, sulfa drugs), the inheritance is not. Neurofibromatosis, whose occurrence is often sporadic (ie, a spontaneous mutation in 50%), is inherited as an autosomal dominant trait once the gene is in a family. The severity of the condition can be quite variable even within the same family. The human leukocyte antigens (HLAs) (four from each parent) are all expressed and therefore do not show any dominance in their expression. Certain combinations of haplotypes are associated with some disease conditions (such as 21-hydroxylase deficiency congenital adrenal hyperplasia, which is autosomal recessive) in that they occur much more commonly than would be expected by chance; however, such associations do not, alone, define inheritance. Cystic fibrosis is the most common autosomal recessive disorder in the white European population, and Huntington disease is autosomal dominant.