Cerebrotendinous Xanthomatosis (CTX) is an autosomal recessive disorder of bile acid and lipid metabolism caused by mutation of CYP27A1 gene, coding for mitochondrial enzyme sterol 27 hydroxylase, resulting in decreased bile acid synthesis with resultant increase in cholesterol synthesis and shunting of cholesterol to its reduced form cholestanol, which then accumulates in various tissues. Cholestanol crosses blood brain barrier and is responsible for peripheral manifestations of CTX: tendinous and tuberous xanthomas, dementia and personality changes, atherosclerosis and cataracts. It is a rare disorder with only 300 cases reported worldwide. Bile acid replacement with chenodeoxycholic acid (CDCA) normalizes cholestanol level through downregulation of 7 αhydroxylase enzyme (which is a rate limiting step of bile acid synthesis); and improve symptoms. 
A 38 year old Caucasian male presented with lumps on hands, feet and back for 20 years. He treated with Chenodeoxycholic Acid. He developed progressive learning disability starting when he was in 8th grade. He had chronic diarrhea since childhood ineffectively treated as lactose intolerance. His father had premature CAD (4 myocardial infarctions, the first at age 42), and a recent CVA. At the age of 38, he was referred to a surgeon for biopsy of the lump on his left Achilles tendon, which was consistent with a tendinous and tuberous xanthoma. He was referred to endocrinology for further management.
Liquid chromatography / mass spectrometry / mass spectrometry, by retention time, molecular weight and secondary information of compound "Qingkailing" injection of acid,  qualitative deoxycholic acid and chenodeoxycholic acid; establishment a quantitative analysis method internal standard method of compound in a relatively high content of bile acids; results showed that bile acids in 875ng / L ~ 140μg / L linear range, linear correlation coefficient R2 = 0.9999; RSD = 2.4%. The method is simple, high selectivity and sensitivity. It has important implications for the quality control of traditional Chinese medicine.