Re: Darwin’s illness revisited
. Among the more than 40 different diagnoses have been proposed for Darwin’s illness is a more recent proposal that he had Crohn’s disease . This diagnosis was shortly afterwards comprehensively refuted .
The diagnosis of Crohn’s disease however has lately been revived, see Channel 4 (UK) documentary: ‘Dead Famous DNA reveals Charles Darwin suffered from Crohn's disease’ ( https://listserv.nodak.edu/cgi-bin/wa.exeA2=ind1404a&L=co-cure&F=&S=&P=1... ). This revival is based on the DNA analysis of hairs from Darwin’s beard and the finding of ’21 markers for Crohn’s disease, five of them being diagnostic, including the major marker on chromosome 16’ .
A diagnosis of Crohn’s disease does not explain Darwin’s most troublesome symptoms of episodic nausea, vomiting and flatulence. It does not explain his visual disturbances, his severe headaches, the periods of incapacitating lethargy, his seasickness and his autonomic symptoms of heat and cold intolerance, dizziness and giddiness. Psychiatric symptoms of unexplicable fear and hysterical sobbing are unaccounted. It does not explain Darwin’s eczema and his recurrent boils. It does not explain his attacks being brought on by pleasurable events (‘positive stress’) or his relief from the ‘water cure’and finally, it does not explain his maternal family history of illness. It is just possible that Darwin did have Crohn’s disease and this might explain his episodes of abdominal pain and probable episodes of fever but not his other numerous symptoms.
The markers on chromosome 16 only confer a susceptibility to the disorder, with a genotype-relative risk for the major marker of 1.5 for heterozygous and 17.6 for homozygous, compared with wild-type controls . The genetic evidence is hardly conclusive; the clinical evidence is not supportive.
 Orrego, F. & Quintana, C. 2007 Darwin's illness: a final diagnosis. Notes Rec R Soc Lond 61, 23-29.
 Sheehan, W., Meller, W.H. & Thurber, S. 2008 More on Darwin's illness: comment on the final diagnosis of Charles Darwin. Notes Rec R Soc Lond 62, 205-209.
 Jeffries, M. 2014 Dead Famous DNA reveals Charles Darwin
suffered from Crohn's disease. In http://www.mirror.co.uk/tv/tv-news/dead-famous-dna-charles-darwin-3337775 (
 Ogura, Y., Bonen, D.K., Inohara, N., Nicolae, D.L., Chen, F.F., Ramos, R., Britton, H., Moran, T., Karaliuskas, R., Duerr, R.H., et al. 2001 A frameshift mutation in NOD2 associated with susceptibility to Crohn's disease. Nature 411, 603-606. (doi:10.1038/35079114).
Competing interests: original author