PMM2 and retinitis pigmentosa: As patients reach their teenage years and young adulthood, health challenges include hypogonadism, coagulation abnormalities and thrombotic events, retinitis pigmentosa and peripheral neuropathy (Monin et al., 2014) The prognosis for PMM2-CDG patients is poor and there is currently no FDA-approved treatment that alleviates the symptoms of PMM2-CDG or any targeted therapy that safely increases PMM2 enzyme activity.