X-LINKED SEVERE COMBINED IMMUNODEFICIENCY

Description:

(X-SCID) is due to defects in the common gamma chain (gamma-c, interleukin-2 receptor gamma [IL2RG])

Symptoms:

  • Infections very early in life
  • Rashes
  • Diarrhea
  • Cough and congestion
  • Fevers, pneumonia
  • Sepsis and other severe bacterial infections
  • Short stature
  • Viral infections such as pneumonitis
  • Inflammation of the lung
  • Candidiasis
  • Recurrent eczema
  • Failure to thrive
  • Gut problems
  • Skin problems
  • Muscle hypotonia

Causes:

  • Mutations in the IL2RG gene
  • Profound derangement of the immune system via the blockade of multiple cytokine pathways
  • Occurs due to decreased amount of immunoglobulin G (IgG) levels
  • Recurrent infections and nutritional deficiencies

Risk Factors:

  • Affects at least 1 in 50,000 to 100,000 newborns
  • The risk is the same for males and females (manifest mostly in males)
  • Newborn babies with SCID-gain weight, risk of having recurrent infections
  • A family history of immune deficiency or infant deaths due to infections

Diagnostic Tests:

  • Newborn screening
  • Lymphocyte count
  • Genetic testing
  • Lymphocyte subset enumeration by flow cytometry
  • Chest X-rays
  • Molecular testing of IL2RG

Differential Diagnosis:

  • Agammaglobulinemia
  • B-Cell and T-Cell Combined Disorders
  • Cartilage-Hair Hypoplasia
  • Cutaneous Manifestations of HIV Disease
  • Graft Versus Host Disease
  • Hyperimmunoglobulinemia E (Job) Syndrome
  • Immunologic Aspects of DiGeorge Syndrome
  • Lymphohistiocytosis (Hemophagocytic Lymphohistiocytosis)
  • Lymphoproliferative Disorders
  • Pediatric Atopic Dermatitis
  • Pediatric Bruton Agammaglobulinemia
  • Pediatric HIV Infection
  • Sinonasal Manifestations of Cystic Fibrosis
  • T-Cell Disorders
  • Wiskott-Aldrich Syndrome
  • X-linked Immunodeficiency With Hyper IgM

Treatments:

  • Stem cell transplant
  • Bone marrow transplantation
  • Enzyme replacement therapy
  • Gene therapy
  • Administration of immunoglobulin

Lifestyle Management:

  • Genetic counseling
  • Treatment of manifestations by BMT
  • Preventative measures to avoid any infections