This is a pilot study of up to 10 patients with Osteoporosis-pseudoglioma syndrome (OPPG) from the Old Order Mennonite community, who will be given lithium for 6 months and have dual energy xray absorptiometry (DXA), peripheral quantitative computerized tomography (pQCT) and lab assessment at baseline and 6 months. Studies in the mouse model of OPPG showed that lithium normalized their bone strength. Controls (n=20) will be recruited from the Old Order Mennonite community, to minimize the effects of environmental and lifestyle factors. The controls will not be given lithium. The age range of participants will be 4-64 years.