My boys have both been diagnosed with the genetic condition, Ocular Albinism — Will in August of 2009 and Jack in November 2010. Ocular Albinism is a condition in which the eyes lack melanin pigment in the fovea of the retina causing decreased visual acuity. I have received many questions about the genetics of Ocular Albinism given the complexity of the eye and this rare disease, so let me try to provide some clarity, no pun intended.
The most common form of Ocular Albinism is X-linked where the affected gene is on the X chromosome. Due to the fact that boys have only one X chromosome inherited from their mother, they are most affected by Ocular Albinism. Each time a mother carrying the mutated X chromosome has a baby boy there is a one in two chance that the boy will have Ocular Albinism. Unless the father has Ocular Albinism, girls will either just be carriers or not affected by this type. Based on the diagnosis at Seattle Children’s Hospital, we believe the boys have X-linked Ocular Albinism.
A more rare form of Ocular Albinism is autosomal recessive. In this form both parents carry the recessive gene. In this case, the baby would have to receive an affected gene from each parent to have Ocular Albinism. There is a one in four chance that any children would have Ocular Albinism. Both boys and girls have an equal chance of inheriting the affected genes. Oculocutaneous Albinism (the most severe type of albinism that affects the pigmentation of the skin, hair and eyes) is most commonly autosomal recessive.
The only way to truly identify the type of Ocular Albinism is to conduct a genetics test, however, examination of the mother can help narrow the possibilities. The gene for X-linked Ocular Albinism has been identified at GPR143. We have opted not to do the genetic testing at this time, due to the cost of the procedure and the fact that it doesn’t alter our treatment plan for the boys. We will eventually do the testing so the boys know what odds they are dealing with when it is time for them to start a family. While that choice is ultimately personal, Will has proven that children with this disease can be fully-functioning human beings. And hysterical, larger than life, crazy and the love of our lives.