Wiskott-Aldrich Syndrome | Symptoms & Causes

What are the symptoms of Wiskott-Aldrich syndrome?

Nearly every child with Wiskott-Aldrich syndrome will start showing symptoms as a baby, between the time they're born and the time they turn 1. The symptoms usually include:

  • frequent and easy bleeding that can occur:
  • from the nose
  • from the mouth and gums
  • in bowel movements
  • frequent and easy bruising
  • a small red rash consisting of “dots” under the skin (these are called petechiae)
  • chronic infections
  • eczema (atopic dermatitis)
  • autoimmunity (anemia, arthritis, inflammatory bowel disease, nephritis, vasculitis)

Since Wiskott-Aldrich syndrome is a genetic disorder (caused by an error in the genes), it is always present at birth, however, symptoms may not show up until later in infancy.

What causes Wiskott-Aldrich syndrome?

Wiskott-Aldrich syndrome is a genetic disorder, meaning it is caused by a mutation, or error, in the child’s genes.

Every living organism on this planet is made up of genes — tiny, complex coded instructions that determine what we look like, who we’re related to and how we’ll pass on our traits to our children (and our children’s children). Sometimes, the genes we inherit from a parent also contain mutations, or mistakes in the genetic code.

When the mutation happens on the X chromosome — one of the two chromosomes, X and Y, that determine a person’s gender — it can be passed on by mothers to their sons. Because the mothers have two X chromosomes, even if they have a mutation on one of the two X chromosomes, they still have a normal copy of the gene on the other X chromosome, and therefore they themselves don’t experience any physical problems from the mutation. However they can transmit the X chromosome with the mutation — and the disease it causes — over to their male children. Boys have only one X chromosome, so male babies who inherit from their mother the faulty X chromosome with, will have the disease. Sometimes a boy can be born with the faulty X chromosome, even though his mother is not a carrier of the mutation (in this case, the mutation arises in the germ cell of the mother).

Wiskott-Aldrich syndrome develops as the result of a defect in a gene located on the X chromosome. Because females have two X chromosomes, but males have only one, women who carry a defect of the Wiskott-Aldrich syndrome gene in one of their X chromosomes do not develop symptoms of the disease (because they have a “healthy” X chromosome), but can pass the defective gene on to their male children. As a result, Wiskott-Aldrich syndrome almost always affects boys only.