TXK and hyperinsulinemic hypoglycemia, familial, 4: In TKL-deficiency, patients present with short stature, developmental delay, congenital heart disease, and cataracts.21 TKL-deficiency results in elevated concentrations of several metabolites: Elevated urinary excretion of erythritol, arabitol, ribitol, and pent(ul)ose-5-phosphates, as well as elevated plasma concentrations of erythritol, arabitol, and ribitol.