I have the following symptoms: shortness of breath (3 recent EKGs have shown only Left Branch Bundle Block, and myocardial nuclear infusion shows NO heart problem); recent chest x rays show no issues with lungs, fatigue, numbness in lower extremities, slight cough, unsteadiness in walk; brittle nails; constipation (colonoscopy 3 years ago was clean); recent thyroid test shows that the ##s are OK, but possibly marginal. I haven t gained, or lost, weight, have no other symptoms. I do not smoke (not for 50 years), drink in moderation, get exercise. I am thinking possibly deficient Intrinsic Factor leading to B12 deficiency