***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The relationship between molecular defect and clinical phenotype has been examined in 42 patients with heterozygous familial hypercholesterolaemia ( FH ) and premature coronary heart disease . The defined defects included mutations in the low density lipoprotein (LDL)-receptor gene ( 23/42 ) or the apolipoprotein B Arg3500Gln mutation ( 5/42 ) . Mean LDL-cholesterol was higher , both before and during treatment with simvastatin and bile acid sequestrants , in patients predicted as having a ' severe ' mutation than in those with a ' mild ' mutation ( 8.72 + /- 2.02 mmol/l vs 6.63 + /- 1.8 , P = 0.05 before and 4.51 + /- 0.90 mmol/l vs 3.19 + /- 0.58 , P = 0.05 during treatment ) . Maximum inducible LDL-receptor activity in cultured lymphoblasts was inversely correlated with LDL-cholesterol before ( r2 = 0.499 , P = 0.002 ) and during ( r2 = 0.478 , P = 0.004 ) treatment in patients with a defined mutation in the LDL-receptor gene , but not in the 14 patients with no detectable molecular defect . LDL-cholesterol concentrations before and during treatment were significantly correlated in patients with a defined LDL-receptor gene mutation ( r2 = 0.548 , P = 0.0001 ) , but not in those with no detectable genetic defect . All these correlations were weak , however and there were no differences in the response to treatment in terms of either relative reduction or absolute decrease in LDL-cholesterol concentration between patients with different LDL-receptor defects . We conclude that only part of the variable phenotype of heterozygous FH patients is explained by different LDL-receptor defects and that other factors determine the severity of their hypercholesterolaemia and the onset of coronary disease The relation of peripheral flow-mediated vasodilation and coronary arterial calcium was studied in young patients with heterozygous familial hypercholesterolemia ( FH ) using high-resolution ultrasound and multi-detector computed tomography ( MDCT ) . We found that peripheral flow mediated vasodilation , a precursor of atherosclerosis , is altered in young heterozygous patients with FH . This alteration occurs before coronary arterial or aortic root calcium can be detected by MDCT and is independently related to hypercholesterolemia 
    Output:
    
The risks of myopathy and clinical adverse events were also similar in both groups .
AUTHORS ' CONCLUSIONS Statin treatment is an efficient lipid-lowering therapy in children with familial hypercholesterolemia .
It seems to be safe in the short term but long-term safety is unknown .