- Dandy-Walker malformation
- Deletion 22q11 syndrome
- Dementia
- Dentatorubral-pallidoluysian atrophy
- Depression
- Diabetes
- Diastrophic dysplasia
- Distal arthrogryposis syndrome
- DNA (deoxyribonucleic acid)
- Donohue syndrome
- Down syndrome
- Duane retraction syndrome
- Dubowitz syndrome
- Duchenne muscular dystrophy
- Dysplasia
- Dystonia
