Neurological assessment of gestational age in newborn.

11-78 mg./24 hr.). Free (i.e. non-peptide) hydroxylysine is usually present only in trace amounts, except during a high collagen diet. An excess of free hydroxylysine was found in Case 1 (10 0 mg./24 hr.) and Case 2 (12-3 mg./24 hr.). Case 1 also excreted an excess of citrulline (8 8 mg./24 hr.). Since no hydroxylysine was detected in the fasting bloods of controls or of patients, a renal origin of the aminoaciduria seemed more likely than a metabolic block. Results of hydroxylysine tolerance and renal clearance tests supported this view. Total urinary hydroxyproline was in the upper range of normal. Since hydroxylysine and hydroxyproline in animal tissues are found almost exclusively in collagen, the ratio of these amino acids in urinary peptides might be expected to be constant provided that their rates of further metabolism were similar. This was investigated in 22 subjects on low collagen diets, 19 of whom were normal individuals, and 3 patients with Marfan's syndrome known to have high excretions of urinary total hydroxyproline. After hydrolysis of urinary peptides, a direct relation was found between the excretion of total hydroxylysine and hydroxyproline.