complement component 7 deficiency

Complement component 7 deficiency is an inherited condition caused by mutations in the C7 gene that result in decreased levels of the complement C7 protein, a key component of the immune system. Individuals with this condition characteristically experience recurrent infections with Neisseria bacteria due to impaired immune defense. Although precise prevalence estimates are not well established, the condition is understood to be rare. It typically presents in childhood, although age of onset and severity can vary.

The hallmark features of complement component 7 deficiency include a persistently low level of circulating C7 and recurrent Neisserial infections, both of which are consistently observed in affected individuals. These clinical findings often lead to investigation for an underlying immune deficiency. Not all individuals experience every potential complication, and severity varies considerably from one person to another.

This condition is caused by mutations in the C7 gene, which plays a crucial role in the complement system, a part of the immune response that helps fight off infections. It is inherited in an autosomal recessive pattern, meaning that an affected individual has inherited two mutated copies of the gene, one from each parent. This inheritance pattern implies that each sibling of an affected person has a 25% chance of inheriting the condition, and genetic counseling is recommended for families to understand the risks and implications.

Currently, management of complement component 7 deficiency focuses on supportive care and symptom management rather than specific approved treatments. This approach may include measures such as the use of prophylactic antibiotics and prompt treatment of infections, provided as part of a multidisciplinary team strategy tailored to the individual's needs. Patients are encouraged to discuss treatment options with their healthcare team, and genetic counseling is recommended to help families navigate the implications of the condition.

The outlook for individuals with complement component 7 deficiency can vary widely, with some managing recurrent infections through vigilant care and others experiencing more severe complications. With current standards of care, many individuals are able to live into adulthood, although the clinical course depends on factors such as the frequency of infections and access to specialized care. Outcomes described in medical literature continue to evolve as standards of care improve, and families are encouraged to connect with genetic counselors and specialists to better understand individual risks and management strategies.