Any contestants who refuse to have the ice and water dumped on them are expected to donate at least US$100 to ALS research. As of July 2015, the Ice Bucket Challenge had raised $115 million for the ALS Association. Many celebrities have taken part in the challenge. The Ice Bucket Challenge was credited with helping to raise funds that contributed to the discovery that the gene NEK1 may potentially contribute to the development for ALS. Research
Model organisms
Many different organisms are used as models for studying ALS, including Saccharomyces cerevisiae (a species of yeast), Caenorhabditis elegans (a roundworm), Drosophila melanogaster (the common fruit fly), Danio rerio (the zebrafish), Mus musculus (the house mouse), and Rattus norvegicus (the common rat). None of these models perfectly represents ALS in humans, partly because most animal models are based on gene overexpression, meaning that multiple copies of the mutant human gene are inserted into the transgenic model, and partly because the human nervous system is very different from that of other animals.The first animal model for ALS was the SOD1G93A transgenic mouse, which was developed in 1994. It expresses about 20–24 copies of the mutant human SOD1 gene and reproduces most of the clinical and pathological findings seen in ALS. Although there are now over 20 different SOD1 mouse models, the SOD1G93A model remains both the most widely used SOD1 mouse model and the most widely used ALS mouse model overall. Much of the present understanding of ALS pathophysiology came from studying mouse models that overexpress mutant SOD1, especially SOD1G93A mice.
Men have a higher risk mainly because spinal-onset ALS is more common in men than women. The number of those with ALS in the United States in 2015 was 5.2 people per 100,000, and was higher in whites, males, and people over 60 years old. The number of new cases is about 0.8 people per 100,000 per year in east Asia and about 0.7 people per 100,000 per year in south Asia. About 80% of ALS epidemiology studies have been conducted in Europe and the United States, mostly in people of northern European descent. There is not enough information to determine the rates of ALS in much of the world, including Africa, parts of Asia, India, Russia, and South America. There are several geographic clusters in the Western Pacific where the prevalence of ALS was reported to be 50–100 times higher than the rest of the world, including Guam, the Kii Peninsula of Japan, and Western New Guinea. The incidence in these areas has decreased since the 1960s; the cause remains unknown.People of all races and ethnic backgrounds may be affected by ALS, but it is more common in whites than in Africans, Asians, or Hispanics. In the United States in 2015, the prevalence of ALS in whites was 5.4 people per 100,000, while the prevalence in blacks was 2.3 people per 100,000. The Midwest had the highest prevalence of the four US Census regions with 5.5 people per 100,000, followed by the Northeast (5.1), the South (4.7), and the West (4.4).