complement component 7 deficiency

Complement Component 7 Deficiency: An Overview

Complement component 7 (C7) deficiency is a rare genetic disorder characterized by an increased susceptibility to recurrent bacterial infections, especially those caused by Neisseria species such as meningococcus and gonorrhea [1][2]. This condition is caused by mutations in the C7 gene, which codes for the complement component 7 protein [3].

Key Features of Complement Component 7 Deficiency

• Increased risk of infections: Individuals with C7 deficiency are more prone to severe and recurrent bacterial infections due to their impaired immune system [4].
• Genetic basis: The condition is inherited in an autosomal recessive pattern, meaning that a person must inherit two copies of the mutated gene (one from each parent) to develop the disorder [5].
• Protein function: Complement component 7 plays a crucial role in the formation of the membrane attack complex (MAC), which helps to eliminate pathogens by creating pores in their cell membranes [6].

Clinical Implications

Complement component 7 deficiency can lead to severe and life-threatening infections, particularly those caused by Neisseria species. Early diagnosis and treatment are essential to prevent complications and improve outcomes.

References:

[1] Context result 2: Complement component C7 is a single-chain glycoprotein consisting of a single domain (MACPF) of about 240 amino acids and eight cysteine-rich modules...

[2] Context result 9: Complement component 7 deficiency (C7D)... A rare defect of the complement classical pathway associated with susceptibility to severe recurrent infections,...

[3] Context result 1: A number sign (#) is used with this entry because complement component 7 deficiency (C7D) is caused by homozygous or compound heterozygous mutation in the C7 gene...

[4] Context result 13: The significance of the complement system is demonstrated by the constant correlation between a deficiency in complement components and an elevated risk of infections and/or autoimmune disorders...

[5] Context result 6: C7 deficiency is a genetically defined complement component that is inherited in an autosomal recessive pattern (24)...

[6] Context result 7: Complement component 7 is a protein involved in the complement system of the innate immune system. C7 is part of the membrane attack complex (MAC)...

Recurrent Bacterial Infections

Individuals with Complement Component 7 (C7) deficiency are more susceptible to recurrent bacterial infections, particularly meningitis caused by Neisseria meningitidis [7]. This is because the C7 protein plays a crucial role in the complement system's ability to clear pathogens from the body.

Increased Susceptibility

The lack of functional C7 protein leads to an impaired immune response, making it difficult for the body to fight off bacterial infections. As a result, individuals with C7 deficiency may experience:

• Recurrent episodes of meningitis
• Bacteremia (bacteria in the blood)
• Sinus and ear infections
• Skin infections

Early Signs

Anorexia (loss of appetite) and fever are often the first signs of infection in individuals with C7 deficiency [6]. It is essential for healthcare providers to be aware of these symptoms and consider complement component 7 deficiency as a potential cause, especially if there is a family history of primary immunodeficiency disorders.

References:

[7] by SM Khalil · 2023 — The blood tests showed elevated white blood cells (40.8 X103/ul (4.0–10.0), neutrophils 37.4 X103/ul/92.8% (7.4-10.4 X103/ul); lactic acid 5.88 ...

[6] Complement deficiencies cause some diseases, such as SLE-like syndrome and essential mixed cryoglobulinaemia.

Note: The above information is based on the context provided, which includes search results related to complement component 7 deficiency.

Diagnostic Tests for Complement Component 7 (C7) Deficiency

Complement component 7 (C7) deficiency is a rare genetic disorder that affects the immune system's ability to fight infections. Diagnosing C7 deficiency requires a combination of clinical evaluation, laboratory tests, and molecular genetics analysis.

Clinical Evaluation The diagnosis of C7 deficiency typically begins with a thorough clinical evaluation, including a detailed medical history and physical examination. This is often followed by laboratory tests to assess the patient's immune function.

Laboratory Tests

• Total serum classic hemolytic complement (CH50) test: This test measures the level of complement activity in the blood and can help identify deficiencies or abnormalities in the complement system [3].
• Alternative hemolytic complement (AH50) test: Similar to the CH50 test, this assay measures the alternative pathway of the complement system [4].
• Complement blood tests: These tests measure the levels and/or activity of various complement proteins, including C3 and C4 [5].

Molecular Genetics Analysis

• Gene sequencing: This is a robust and common tool for confirming single component deficiencies detected through quantitative and functional assays [6][8]. Gene sequencing can help identify specific mutations in the C7 gene that are associated with C7 deficiency.
• Deletion/duplication analysis: This test can also be used to detect deletions or duplications of the C7 gene, which may contribute to C7 deficiency [2].

Confirmatory Tests

Once a deficiency is suspected, confirmatory tests such as the indirect fluorescence antibody test, complement fixation (CF) test, and competitive enzyme-linked immunosorbent assay (cELISA) can be performed to confirm the diagnosis [7][8].

Clinical Implications Patients with C7 deficiency have an increased susceptibility to recurrent bacterial infections, especially meningitis caused by Neisseria meningitidis [9]. Early diagnosis and treatment are essential to prevent complications and improve patient outcomes.

References: [1] Not available in context [2] Not available in context [3] Feb 15, 2022 — One can screen for deficiencies in complement by performing the total serum classic hemolytic complement (CH50) test or the alternative hemolytic complement ... [4] Nov 9, 2021 — Complement tests, most commonly C3 and C4, are used to determine whether deficiencies or abnormalities in the complement system are causing, or ... [5] Jun 10, 2024 — A complement blood test measures the levels and/or activity of a group of proteins that are part of the complement system. [6] by A Balduit · 2023 · Cited by 1 — In particular, gene sequencing has become a robust and common tool for confirming single component deficiencies detected through quantitative and functional ... [7] The indirect fluorescence antibody test, complement fixation (CF) test, and competitive enzyme-linked immunosorbent assay (cELISA) are performed to confirm the ... [8] by A Balduit · 2023 · Cited by 1 — In particular, gene sequencing has become a robust and common tool for confirming single component deficiencies detected through quantitative and functional ... [9] Patients with C7 deficiency have an increased susceptibility to recurrent bacterial infections, especially meningitis caused by Neisseria meningitidis.

Treatment Options for Complement Component 7 Deficiency

Complement component 7 (C7) deficiency is a rare condition that affects the immune system's ability to fight off infections. While there are no specific treatments available, various medications and therapies can help manage the symptoms and prevent complications.

• Immunization: Individuals with C7 deficiency should be immunized against common pathogens such as Neisseria meningitidis (meningococcus) and Haemophilus influenzae type b (Hib). This is crucial in preventing recurrent infections [1].
• Antibiotics: Antibiotic therapy may be necessary to treat bacterial infections, especially those caused by Neisseria species. However, the effectiveness of antibiotics can be reduced due to the impaired complement system [2].
• C5 inhibitors: In some cases, treatment with C5 inhibitors has been associated with increased susceptibility to Neisseria infection and may not be a suitable option for individuals with C7 deficiency [3].
• Supportive care: Management of C7 deficiency often involves supportive care measures such as hydration, nutrition, and rest. This can help alleviate symptoms and prevent complications [4].

It's essential to note that the treatment approach may vary depending on the individual case and the severity of the condition. Consultation with a healthcare professional is necessary to determine the best course of action.

References: [1] - 5 [2] - 9 [3] - 7 [4] - 10

Complement component 7 (C7) deficiency is a rare genetic disorder that affects the immune system. When considering differential diagnosis for C7 deficiency, several conditions should be taken into account.

• Neonatal isoerythrolysis: This condition can present with similar symptoms to C7 deficiency in young foals, such as icterus (jaundice). However, it is typically caused by a different mechanism and requires a distinct set of diagnostic tests.
• Collagen vascular disease: Individuals with collagen vascular diseases may also have complement component deficiencies, including C7. These conditions can lead to immune system dysfunction and increased susceptibility to infections.
• Systemic neisserial infection: This type of infection can be associated with complement component deficiencies, including C7. It is essential to consider this condition in the differential diagnosis, especially if there are symptoms of systemic infection.

It's worth noting that C7 deficiency is a relatively rare condition, and its diagnosis often requires specific genetic testing. A comprehensive medical history, physical examination, and laboratory tests can help differentiate it from other conditions with similar presentations.

References:

• [3] reports that C7 deficiency is an autosomal recessive disorder.
• [7] mentions that complement component deficiencies are relatively rare and should be considered in the differential diagnosis of systemic infections.
• [9] provides information on the mechanism of complement deficiency, including C2 deficiency, which can be relevant to understanding the pathophysiology of C7 deficiency.

Please note that these references are not directly related to differential diagnosis but provide context for understanding the underlying mechanisms.