"Diseases" are specific things. They are labels for concepts of ill health. A "disorder" simply means something is not working right

Disease is normally used in the sense of sickness, ‘an illness that disrupts normal physical or mental functions’. disorder is  ‘a state of confusion’. 
Disease, any harmful deviation from the normal structural or functional state of an organism, generally associated with certain signs and symptoms and differing in nature from physical injury. A diseased organism commonly exhibits signs or symptoms indicative of its abnormal state. Thus, the normal condition of an organism must be understood in order to recognize the hallmarks of 

disease. Nevertheless, a sharp demarcation between disease and health is not always apparent.
Dis-ease - A disorderly or abnormally functioning organ or system. 
Condition - describes state of health. i.e. patient was in poor condition
Disorder  : A  condition of the living animal or plant body or of one of its parts that impairs normal functioning and is typically manifested by distinguishing signs and symptoms .
Dis-order - disturbed order. Our body normal works in an orderly fashion. Any anomaly/ aberration from the orderly state. Eg Mental Disorder; Menstrual disorder.
Diabetes is a metabolism disorder
Diabetes (diabetes mellitus) is classed as a metabolism disorder. Metabolism refers to the way our bodies use digested food for energy and growth. Most of what we eat is broken down into glucose. Glucose is a form of sugar in the blood - it is the principal source of fuel for our bodies
Syndrome -. Involved of multiple organs/ organ systems with specific symptoms and signs. AIDS (Acquired Immune Deficiency Syndrome). 
Metabolic syndrome:
A cluster of conditions that increase the risk of heart disease, stroke and diabetes.
Metabolic syndrome includes high blood pressure, high blood sugar, excess body fat around the waist and abnormal cholesterol levels. The syndrome increases a person's risk of heart attack and stroke.
Aside from a large waist circumference, most of the disorders associated with metabolic syndrome have no symptoms.
Weight loss, exercise, a healthy diet and smoking cessation can help.