Discovery Solves Mystery of Inherited Disease By Marc Kusinitz Johns Hopkins eye doctors have discovered the common cause of dramatic damage to both the eyes and brains of babies born with a rare inherited disease called incontinentia pigmenti. IP can appear in many forms, such as lack of skin pigment, rash, bald spots on the top of the scalp, missing or deformed teeth, seizures and other mental disorders, and detached retinas, bleeding into the eye and other eye disorders. The identification of this cause--blockage of small blood vessels--solves a long-standing mystery about seemingly unrelated symptoms, they say. And the discovery offers physicians a simple routine eye test to identify IP in newborns, and in some cases prevent blindness with prompt therapy. The finding is reported in the May issue of Archives of Pediatrics and Adolescent Medicine. "IP develops over the first few weeks of life," said Morton Goldberg, director of the Wilmer Eye Institute at Johns Hopkins. "Blood vessels in the brain and retina close down, and the tissues they feed die. The baby can develop epilepsy, mental retardation, paralysis or spasticity (involuntary muscle twitching), or blindness." According to Dr. Goldberg, quick treatment can sometimes save the baby's sight. "In some cases, we can slow retinal damage with a laser," he said. "Or, if the retina has become detached from the back of the wall, we can reattach it surgically." IP, which affects fewer than one in 200 newborns in the United States, is an X-linked disorder. That is, it is inherited from the mother on the X, or female, chromosome. The disease often first appears in newborns as a simple rash that looks like chicken pox. The rash disappears over several months' time. Although some people never suffer further problems, others later experience severe symptoms. According to Dr. Goldberg, all patients diagnosed with IP should quickly be seen by an ophthalmologist. In addition, because severe brain damage is usually accompanied by serious retinal damage, patients with severe retinal disease should also be examined for the presence of brain damage. Using special imaging techniques, the Hopkins researchers identified areas in the brains of seven patients with IP where blood vessels were blocked. One technique called magnetic resonance angiography, permits researchers to study blood vessels in the brain. The other technique, MR spectroscopic imaging, permits them to study various metabolites--breakdown products of food. The Hopkins team used SI to detect the presence of lactate, which is formed by cells that are starved for oxygen. The researchers found that the extent of blood vessel blockage in the retina correlates with the severity of brain damage.
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