Hi Dear, Welcome to HCM. Understanding your concern. As per your query you have dark discoloration in feet and hands along with gluteal muscle cramps . Well there can be many reasons for symptoms you mention in query like peripheral neuropathy , diabetes , vitamin B12 deficiency , low blood sugar and iron level .Organ failure like kidney and liver can also cause such problem. It could also be due to more serious problem like cardiac problem. I would suggest you to consult general practitioner for proper examination . Doctor may order blood test , ECG , and check vitals to confirm the diagnosis . Doctor may also order liver and kidney function test. Doctor may prescribe supplements like iron or vitamin B 12 . Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari