child with high cholestrol

recently my son who is 6 years was found with high cholesterol (7.73 mmol/L) , LDL ( 6.21 mmol/L) , HDL (1.19 mmol/L) , triglycierides ( 0.73 mmol/L) ,  plus his ALT ( 60 U/L) and AST ( 63 U/L) ,, they did ultra-sound for his liver they said it's okay ,my son has a normal weight and our food is balanced not faty , my question is what could be the reason for this , what kind of treatment at this age , and which medecine speciality is dealing with this kind of problem ,  , my self and my wife dont have any cholestrol history and my mother has developped high cholestrol with time at 66 years old when she has to do a by pass operation !

[Marie M Gleason, M.D.]

Dear hamid1969:  Your son’s total cholesterol level of 7.7 mmol/L is well above the target range which is less than 3.9 mmol/L. His LDL level of 6.2 mmol/L is well above the target of 2.5 mmol/L.  His HDL of 1.19 mmol/L is normal, as is his triglyceride level of 0.73 mmol/L (target less than 1.1 mmol/L).  This pattern of hyperlipidemia is called Familial Hyperlipidemia (FH).  It occurs when the patient’s liver receptors for LDL cholesterol are missing or function abnormally.  As such, their body makes inappropriate amounts of cholesterol.   A person with this form of hyperlipidemia will have very high cholesterol levels, even if they observe a very strict diet.   Since the high cholesterol builds up in blood vessels over time, patients are more prone to coronary artery disease and heart attacks starting in their 30’s and 40’s.  
This is a genetic condition that can be passed from one generation to the next.  If you and your wife have normal cholesterol levels, then this is likely a new mutation for your son, meaning he is the first person in your family to have this condition.  You need to make sure that both of you are checked, and if you have other children, get their cholesterol levels checked also.
Familial hyperlipidemia is best treated with medications to lower cholesterol, called statins.  These medications prevent some of the production of cholesterol by the liver.  Generally these are not started in children until after 10 years of age. Watching diet is also important, but it is not sufficient to lower the cholesterol to the desired levels.  If you have access to a cardiologist, endocrinologist or gastroenterologist who is a lipid specialist in your region, you should try to get evaluated there