Hello...my son is 1.7 years and cant walk.he was diagnosed Jim rickets and was put on supplements for 6months. Now the problem is that he is bending his legs while standing and cannot stand for long,also his hand eye coordination is poor and he grasps things with clenched fists. A bone chemistry done showed calcium was normal but alkaline phosphatase was high. An xray done recently shows that his bone density is normal,a tsh test was okay but pth was abit alow..i think 7.3(i cant recall the units)but the range was 15. Vitamin d levels were 108,the range was less than 200..the boy weighs 12.6 kgs..his muscles appears to be so stiff..what could be causing this?a concerned parent,thnks in advance