In both galactokinase and epimerase
deficiency, children are generally asymptomatic and experience few or no ill effects from lack of the particular enzyme.
On the other side, inositol imbalance might be partially explained with epimerase function failure: in fact, in a rat model of type II diabetes, conversion from MI to DCI in insulin-sensitive tissues was found to be reduced from 20 to 30% to 5% compared to normal rats .
The ovaries are sensitive to insulin and according to DCI ovary paradox theory, increased DCI level, due to increased epimerase function within the ovaries, is associated with a local MI deficiency and poor oocyte quality .
There is only evidence that both myo-inositol to chiro-inositol epimerase activities and chiro-inositol to myo-inositol ratios are decreased in tissues of GK type 2 diabetic rats, potentially playing a role in explaining the decreased chiro-inositol to myo-inositol urine and tissue ratios observed in animal and human studies .
Larner, "Both myo-inositol to chiro-inositol epimerase activities and chiro-inositol to myo-inositol ratios are decreased in tissues of GK type 2 diabetic rats compared to Wistar controls," Biochemical and Biophysical Research Communications, vol.
Clinical 1 No clinical abnormality 2 FNA 3 FNA 4 FNA 5 Epimerase
deficiency 6 Epimerase
deficiency 7 Epimerase
deficiency (mild) 8 FNA 9 FNA 10 FNA 11 Epimerase
deficiency (profound) 12 Epimerase
deficiency (transient) 13 Het D/G 14 Het D 15 Het D/G 16 Het D 17 Het D/G 18 Het D 19 No abnormality 20 FNA (a) To convert Gal concentrations to milligrams per deciliter, divide by 0.
Patients with hIBM and DMRV (also known as Nonaka myopathy) have biallelic missense mutations in the epimerase
and/or kinase domains of the GNE gene.
Particular emphasis is placed on epimerases
and racemases, sugar nucleotide-modifying enzymes, and the enzymes of sialic acid and peptidoglycan biosynthesis.