missing many merging classes

[nlwashington]

as i've been looking through our uberdisease ontology, i've found some issues.

many of the classes in the merged.obo are missing seemingly pedantic grouping classes.

for example,

id: OMIM:614480
name: Hypertriglyceridemia, Transient Infantile
is_a: DOID:630 ! genetic disease

id: OMIM:145750
name: familial hypertriglyceridemia
def: "A lipid metabolism disorder characterized by elevated triglyceride levels as a result of excess hepatic production of VLDL or heterozygous LPL deficiency." [url:http://en.wikipedia.org/wiki/Familial_hypertriglyceridemia]
comment: OMIM mapping confirmed by DO. [SN].
synonym: "Pure hyperglyceridemia" EXACT []
xref: DOID:0050527
is_a: DOID:3146 ! lipid metabolism disorder
is_a: DOID:630 ! genetic disease

are not related to one another except for both being genetic diseases. why isn't the former also a lipid metabolism disorder? or even better, why aren't they both classified as "hypertriglyceridemia"? that seems like a natural grouping class.

another

id: OMIM:606170
name: Genitopatellar Syndrome
is_a: DOID:630 ! genetic disease

in the text there is the description, "The SBBYS variant of Ohdo syndrome (603736) is an allelic disorder with overlapping features."

but it is also not classified:
[Term]
id: OMIM:603736
name: Ohdo Syndrome, Sbbys Variant
is_a: DOID:630 ! genetic disease

so i'd think they would be grouped together in some way.

when i just browse the ontology in protege, if you look under "genetic disease" there are many things that are siblings, but have nearly identical names, suggesting they should be subclasses of a more general disease, but are instead just a big fat flat list. some examples pulled only from A:

Acyl-coa Dehydrogenase * Deficiency Of
Adams-oliver Syndrome
Adrenal Hyperplasia, Congenital
Arthrogryposis * (only 3 of the 6 are classified as subtypes)
Atrial Fibrillation (only 4 of 8 are classified as subtypes)
Atrial Septal Defect (only 4 of 8 are classified as subtypes) ...
in fact, 2257 of the omim diseases in the merged file can't be classified into any upper-level grouping class at all except for a plain "genetic disease", which isn't too helpful.