User:Rgrosland/Krabbe Disease

Epidemiology
This disease does not only impact humans, but other animals such as monkeys, mice, and dogs have been observed to have Krabbe disease as well. While certain gene deletions are more frequent than others, novel mutations resulting in Krabbe disease have been observed worldwide. Most commonly, the underlying cause of the disease is a deletion of a GALC gene, which causes a deficiency in the GALC enzyme. This is the circumstance in 80% of cases who have European and Mexican origins. The mortality rate of early infantile Krabbe disease is 90% before the age of two. Later onset of symptoms is associated with longer life expectancy, with older children generally surviving two to seven years after the initial diagnosis.

Krabbe disease occurs in about one in 100,000 births. Because the disease is genetic, incidence rates vary widely from population to population. The incidence rate is extremely low in Japan, with between 5 and 10 cases per 1,000,000 live births. In the United States, Krabbe disease occurs in approximately 1 out of every 100,000 live births. Scandinavian countries report incidence rates of one in 50,000 births. In certain communities Krabbe disease is much more frequent, such as the Druze community in Israel, which has an incidence rate of 6 out of every 1,000 live births. This higher rate is thought to be due in part to a high frequency of consanguineous marriages. Almost 35% of all Druze marriages were found to be between first-cousin familial relations. There have been no reported cases of Krabbe disease among the Jewish community.

Time of onset also varies in frequency by location. Early infantile Krabbe Disease is the most common form of the disease overall, but Nordic communities tend to have even higher rates of early infantile onset Krabbe disease, while Southern European countries have higher incidences of late-onset cases. It is difficult to estimate the incidence of adult-onset Krabbe disease, due to discrepancies in labeling cases late-onset versus adult-onset.