Metabolomic Characterization of Laron and Guevara-Rosenbloom Syndromes Using UHPLC-HRMS

Laron syndrome (LS) is a rare autosomal recessive growth hormone (GH) insensitivity condition due to GH receptor mutation, and with phenotypic features likened to GH deficiency. The incidence of LS in Ecuador is very high and has gained worldwide attention due to its low incidence of cancer and diabetes mellitus. A more recently described population is affected with “Guevara-Rosenbloom syndrome” (GRS). While both groups exhibit severe short stature (-4 to -12 SDS), GRS subjects have normal GH signaling and responses and, unlike LS, have intrauterine growth retardation and early onset type 2 diabetes (T2DM). Since both groups have diminished insulin secretion, there is a unique opportunity to investigate their metabolome under each specific disease. Levels of certain amino acids in insulin-resistant (IR) states such as T2DM are distinct and special attention has been given to the predicting power of branched chain and aromatic amino acids, carnitines, and free fatty acids for IR and T2DM risk assessment. Our aim was to understand the metabolic differences between LS and GRS, which both have diminished insulin secretion but different GH counter-regulation as well as to compare these groups to normal controls. The metabolome of these 3 cohorts was assessed at the following instances: a) At the fasting state, and b) After an oral challenge of 1.5 mg/kg of glucose per kilogram of body weight, administered immediately after the fasting sample was drawn (samples were taken every 30 minutes for 5 hours [5h]). Preliminary results (by ANOVA) show a strong correlation, in the fasting state, between the control and the LS groups with clear discrimination from the GRS cohort, as determined by a heatmap of the top 100 features. Furthermore, the analysis of the 5h profile after the glucose challenge in the 3 groups revealed significant correlations in the levels of amino-acids that have been related to the genesis of IR and T2DM. This work represents the first deep-metabolome analysis in this unique study group. Disclosure V. Rubio: None. C.A. Chamberlain: None. C. Wasserfall: None. J. Guevara-Aguirre: None. A. Guevara: None. A.L. Rosenbloom: None. M.A. Atkinson: None. R.A. Yost: None. T.J. Garrett: None. Funding National Institutes of Health (U24DK097209)