Eleveated ast and alt liver enzymes

I am 50 yrs old, non-smoker, non-drinker, and do not take any medication except for vitamin E and calcium pills.  My recent blood test shows AST SGOT of 82 (range is 0-42) and ALT SGPT of 135 (normal range) is 135.  Cholesterol-HDL is 62 LDL is 36 triglycerides of 54 and total cholesterol of 109.  Tested negative or non-reactive for hepatitis A B C.  All readings came out normal except for trace occult blood which was referenced as negative.  Had an ultrasound of the liver, spleen and gallbladder and according to the sonographer everything looks normal...I called my sister in the Philippines about my situation and she informed me that she also has elevated AST and ALT readings a month ago.  I had my blood test 14 Nov 2000...I exercise, eat lots of fish, fruits and vegetables...Can this liver enzyme elevation be inherited because my sister has the same problem???  We don't know if our mother has this problem and our father died in 1984.  What other tests should I need done?  Or should I just have a liver biopsy?  Please give me information on this.  Thanks so much....I do not take any herbal medications or herbal teas.....I'm puzzled.....