Use in clinical context
Humans usually have two copies of each autosome, and therefore two copies of each gene. Symptoms associated with autosomal recessive conditions present when both copies of the gene have a pathogenic variant. This can be the same pathogenic variant (homozygous state) or two different pathogenic variants (compound heterozygous state). Which autosomal recessive variants are present can influence the development and presentation of these conditions. In addition, there may be modifying factors such as additional genetic variants and/or environmental factors.
In some cases, signs and symptoms of the condition may not present, even in the presence of a pathogenic variant in each copy of the gene. In other cases, signs and symptoms can vary, for example in autosomal recessive polycystic kidney disease, which typically presents in childhood but in some cases can be identified in older adults.