Skip to main content

X-linked agammaglobulinemia (XLA)

X-linked agammaglobulinemia (XLA)



Overview

X-linked agammaglobulinemia (XLA), or Bruton's agammaglobulinemia, is a rare inherited immunodeficiency caused by mutations in the BTK gene, preventing B-cell maturation and resulting in very low antibody levels. Primarily affecting males, it leads to recurrent bacterial infections, commonly starting at 6-9 months old, requiring lifelong immunoglobulin replacement therapy.

Symptoms

Recurrent Infections: Frequent, persistent, or severe infections of the ears (otitis media), sinuses (sinusitis), nose (rhinitis), and lungs (pneumonia, bronchitis).

Respiratory Infections: Bacterial pneumonia is common and, when it occurs in infants, is a strong indicator of XLA.

Skin and Eye Infections: Abscesses, pyoderma, and conjunctivitis (pink eye).

Gastrointestinal Issues: Chronic diarrhea, often due to a lack of IgA antibodies. 

Serious Infections: Sepsis (blood poisoning), meningitis (spinal cord infection), and septic arthritis.

Physical Findings: Small or absent tonsils and lymph nodes due to low B-cell count.

Causes

BTK Gene Mutation: The mutation prevents the production of functional BTK protein, which is crucial for B-cell development.

B-cell Maturation Arrest: Without functional BTK, B-cell development stalls at the pre-B-cell stage in bone marrow, preventing the formation of mature B lymphocytes.

Antibody Deficiency: Because mature B cells (which turn into plasma cells) are absent, the body cannot produce adequate antibodies (immunoglobulins).

Inheritance Pattern: Because the mutation is on the X chromosome, males (XY) with the mutated gene will have the disease. Females (XX) are usually carriers if they have one affected X chromosome.

Diagnosis

Medical History: Recurring bacterial infections, particularly respiratory and ear infections, typically appearing after 6–9 months when maternal antibodies wane.

Laboratory Tests: Serum Immunoglobulins: Very low levels of IgG, IgA, and IgM.

Flow Cytometry: Almost complete absence of CD19+ or CD20+ B cells.

Antibody Response: Failure to produce antibodies to vaccinations.

Genetic Testing: Identification of a mutation in the \(BTK\) (Bruton's tyrosine kinase) gene.

Treatment

Immunoglobulin Replacement Therapy (IGRT): This is the mainstay of treatment, providing antibodies (IgG) that the body cannot produce.

Intravenous (IVIG): Usually administered every 3–4 weeks, according to Medscape.

Subcutaneous (SCIG): Often administered weekly at home, as described in StatPearls and PMC.

Goal: Maintain IgG trough levels of \(500–800 \text{ mg/dL}\), note Medscape.

Antibiotic Therapy: Prompt and often aggressive use of antibiotics is necessary for treating infections. Prophylactic (preventive) antibiotics may be used for chronic, persistent infections, particularly to prevent sinusitis and pneumonia, 

Avoidance of Live Vaccines: Individuals with XLA must avoid live viral/bacterial vaccines, such as MMR, oral polio, rotavirus, and nasal influenza .

Monitoring and Care: Regular check-ups with an immunologist, often every 6–12 months, are required to monitor for complications.

Type of Doctor Department : A pediatric or adult immunologist

Comments

Post a Comment

Popular posts from this blog

Charge Syndrome

Overview CHARGE syndrome is a recognizable genetic syndrome with known pattern of features. It is an extremely complex syndrome, involving extensive medical and physical difficulties that differ from child to child. CHARGE syndrome is correlated with genetic mutation to CHD7 and the prevalence of CHARGE syndrome is 1:10,000-1:15,000 live births. Babies with CHARGE syndrome are often born with life-threatening birth defects. They spend many months in the hospital and undergo many surgeries and other treatments. Swallowing and breathing problems make life difficult even when they come home. Most have hearing two little girls sitting on a carpet, one girl has a trach and is biting her finger.loss, vision loss, and balance problems that delay their development and communication. Despite these seemingly insurmountable obstacles, children with CHARGE syndrome often far surpass their medical, physical, educational, and social expectations. One of the hidden features of CHARGE syndrome is the ...
7 comments
Read more

Dehydration Due to Diarrheal Diseases

Overview Dehydration occurs when you use or lose more fluid than you take in, and your body doesn't have enough water and other fluids to carry out its normal functions. If you don't replace lost fluids, you will get dehydrated. Anyone may become dehydrated, but the condition is especially dangerous for young children and older adults. The most common cause of dehydration in young children is severe diarrhea and vomiting. Older adults naturally have a lower volume of water in their bodies, and may have conditions or take medications that increase the risk of dehydration. This means that even minor illnesses, such as infections affecting the lungs or bladder, can result in dehydration in older adults. Dehydration also can occur in any age group if you don't drink enough water during hot weather — especially if you are exercising vigorously. You can usually reverse mild to moderate dehydration by drinking more fluids, but severe dehydration needs immediate medical treatment. ...
Post a Comment
Read more

Vogt-Koyanagi-Harada (VKH) Disease

  Vogt-Koyanagi-Harada (VKH) Disease Disease Overview Vogt-Koyanagi-Harada disease is a rare disorder of unknown origin that affects many body systems, including as the eyes, ears, skin, and the covering of the brain and spinal cord (the meninges). The most noticeable symptom is a rapid loss of vision. There may also be neurological signs such as severe headache, vertigo, nausea, and drowsiness. Loss of hearing, and loss of hair (alopecia) and skin color may occur along, with whitening (loss of pigmentation) of the hair and eyelashes (poliosis). Signs & Symptoms Vogt-Koyanagi-Harada disease is initially characterized by headaches, very deep pain in the eyes, dizziness (vertigo), and nausea. These symptoms are usually followed in a few weeks by eye inflammation (uveitis) and blurring of vision. This may occur in both eyes at the same time or in one eye first and, a few days later, in the other. The retina may detach and hearing loss may become apparent. The chronic stage follows...
Post a Comment
Read more