Krabbe disease is a genetic disorder inherited by the expression of an autosomal recessive gene pattern responsible for producing a dominant trait. Specifically, the dominant trait involved with this disease is the formation of globoid cells, which are defined as cells with multiple nucleuses. This abnormal development leads to the damage and ultimate deterioration of the myelin sheath, the protective layer of many nerves that also lends pigment to the “white matter” of the brain. Sadly, Krabbe disease, for which there is no cure, most commonly affects infants less than six months old, often with fatal results.
While this disorder involves a recessive gene, Krabbe disease is classified as a member of the family of degenerative disorders known as leukodystrophies. However, each leukodystrophy involves a different myelin regulating gene, which may be X-linked, dominant, or recessive. In spite of this difference, all of these disorders directly cause the destruction of myelin and white matter of the brain, just by a different mechanism. The particular genetic factor involved in Krabbe disease is a mutation of the GALC gene, which results in a lack of galactosylceramidase, one of the enzymes needed to regulate myelin metabolism.
As previously mentioned, Krabbe disease usually appears in infants, typically between three and six months of age. However, most of the time these infants appear perfectly normal at birth. It’s not until a delay in motor development is noted that this disorder may be suspected. Additional symptoms of onset include seizures and stiff limbs. These symptoms may be accompanied by difficulty feeding with frequent vomiting, which are often mistakenly attributed to colic.
In very rare cases, Krabbe disease may be late onset and present itself in older children and even adults, who typically experience a slower progression of the disease with milder symptoms. Generally, however, the prognosis is poor for children under the age of two years. In fact, the majority of these children succumb to the disease. However, Hunter Kelly, the son of former Buffalo Bill’s quarterback, Jim Kelly, lived to the age of eight despite being diagnosed with this disorder in early infancy. In honor of his son, Kelly and his wife formed The Hunter's Hope Foundation, a non-profit organization dedicated to providing resources and support to parents of children with Krabbe disease.
Treatment for Krabbe disease is minimal and generally intended to address overt symptoms. However, some research indicates that the donation of bone marrow or umbilical cord blood (stem cells) to recipients diagnosed early has shown to be of some benefit. Meanwhile, research led by the National Institutes of Health and The National Institute of Neurological Disorders and Stroke continues. Other organizations that provide support and resources in addition to Hunter’s Hope include the Myelin Project and the United Leukodystrophy Foundation.
