Clinically, 50% of people with ALS have some cognitive or behavioral impairments and 5–15% have FTD, while 40% of people with FTD have some motor neuron symptoms and 12.5% have ALS. Pathologically, abnormal aggregations of TDP-43 protein are seen in up to 97% of ALS patients and up to 50% of FTD patients. In December 2021 a paper found the TDP-43 proteinopathy is in turn caused by defective cyclophilin A which regulates TARDBP gene expression. Other genes known to cause FTD-ALS include CHCHD10, SQSTM1, and TBK1. Environmental factors
Where no family history of the disease is present – around 90% of cases – no cause is known. Possible associations for which evidence is inconclusive include military service and smoking. Although studies on military history and ALS frequency are inconsistent, there is weak evidence for a positive correlation. Various proposed factors include exposure to environmental toxins (inferred from geographical deployment studies), as well as alcohol and tobacco use during military service.A 2016 review of 16 meta-analyses concluded that there was convincing evidence for an association with chronic occupational exposure to lead; suggestive evidence for farming, exposure to heavy metals other than lead, beta-carotene intake, and head injury; and weak evidence for omega-3 fatty acid intake, exposure to extremely low frequency electromagnetic fields, pesticides, and serum uric acid.In a 2017 study by the United States Centers for Disease Control and Prevention analyzing U.S. deaths from 1985 to 2011, occupations correlated with ALS deaths were white collar, such as in management, financial, architectural, computing, legal, and education jobs.
See also
List of radiographic findings associated with cutaneous conditions

References
External links
01061 at CHORUS