MedGen

The pathogenesis of HIV infection and the progression from infection to AIDS vary significantly between exposed individuals. Infection occurs after the virus, which has macrophage (M)- and T lymphocyte (T)-tropic strains and more than 12 subtypes, survives an array of nonspecific, nongenetic environmental and host factors. [from OMIM]

Mycobacterium tuberculosis latently infects approximately one-third of humanity and is comparable only to human immunodeficiency virus (HIV; see 609423) as a leading infectious cause of mortality worldwide. Obstacles for controlling TB infection include lengthy treatment regimens of 6 to 9 months, drug resistance, lack of a highly efficacious vaccine, and incomplete understanding of the factors that control infectivity and disease progression. Although only 10% of individuals infected with M. tuberculosis develop active disease, the immune responses associated with TB susceptibility or resistance are not known. In addition, it is not known why some individuals have disseminated TB that spreads to the meninges and central nervous system, while most people have localized disease in the lungs. A number of studies suggest that host genetic factors influence susceptibility and resistance to TB (review by Berrington and Hawn, 2007). [from OMIM]

A neural tube defect arises when the neural tube, the embryonic precursor of the brain and spinal cord, fails to close during neurulation. The cranial region (anencephaly) or the low spine (open spina bifida; myelomeningocele) are most commonly affected although, in the severe NTD craniorachischisis, almost the entire neural tube remains open, from midbrain to low spine. [from HPO]