"functional deficiency" is correct and usable in written English.
It generally refers to a problem or issue with a system or process not operating as expected or intended. For example, "The team identified a functional deficiency in their software development process, leading to a delay in product releases."
This study investigates the functional deficiency in hypocretin/orexin neurons in Prader-Willi Syndromodelsmodelsdels.
The functional deficiency is accompanied by a decreased association of telomerase with telomeres.
Metachromatic leukodystrophy (MLD) is an inherited lysosomal storage disorder resulting from a functional deficiency of arylsulfatase A (ARSA), an enzyme that catalyzes desulfation of 3-O-sulfogalactosylceramide (sulfatide).
Current treatments of VML are not able to address the functional deficiency of the damaged muscles due to a lack of effective regeneration.
In "repairing" a structure, the composite material is used to fix a structural or functional deficiency such as a crack or a severely degraded structural component.
Background: Sjögren's syndrome (SS) is an autoimmune exocrinopathy associated with multiple autoantibodies, lymphocyte infiltration of various organs, and functional deficiency of T cells.
Mutations in the MMACHC gene (cblC complementation group) disrupt processing of the upper-axial ligand of newly internalized cobalamins, leading to functional deficiency of the vitamin.
Functional deficiency occurring during the leg lengthening has neuropathic, myopathic and arthropathic aspects.
As a partial D2 receptor agonist, aripiprazole may therefore be well placed to correct both a functional deficiency and overactivity.
The negative correlation between metabolism and cognitive scores means that hypermetabolism is associated with a functional deficiency of the involved brain area.
A p95/nbs1 construct mutated at the ATM phosphorylation site abrogated an S-phase checkpoint induced by ionizing radiation in normal cells and failed to compensate for this functional deficiency in NBS cells.
