Classes with a single subclass

'clinical protocol'
'clinical subject role'
'comparative description'
'data item'
'deoxyribonucleotide sequence position'
'diagnostic role '
'drug interaction'
'expert role'
'formulated pharmaceutical'
'genomic sequence'
'human population'
'length value'
'mass per unit time'
'mass value'
'medical descriptor'
'medical finding'
'medical history'
'molecular structure description'
'physical description'
'ranged numerical quantity'
'scale numerical value'
'side effect'
'spatial positional datum'
'subject role'
age
algorithm
allele
assay
date
diagram
dose
hypothesis
image
measure
numeral
organization
patent
publication
quantity
ratio
report