National Organization for Rare Disorders (NORD): www.rarediseases.org -
NORD is a federation of voluntary health organizations dedicatedto helping people with rare diseases.
Center for Parent Information and Resources (CPIR): http://www.parentcenterhub.org/disability-landing/ -
CPIR has information about the category of OHI.
US National Library of Medicine (NIH): https://www.nlm.nih.gov/ -
NIH provides links to databases and literature regarding medicalconditions and diseases.