Glucose transporter 1 deficiency syndrome: nutritional and growth pattern phenotypes at diagnosis.

BACKGROUND/OBJECTIVES: Glucose Transporter 1 Deficiency Syndrome (GLUT1-DS; OMIM #606777) is a rare disease caused by dominant mutations in SLC2A1 encoding GLUT1, which is a ubiquitous transporter of glucose across plasma membranes, particularly across the blood-brain barrier. Hypoglycorrhachia symptoms are the cornerstones of GLUT1-DS, but delayed growth has also been suggested. This led us to investigate, at diagnosis, the relationship between the glycemia/glycorrhachia ratio and the nutritional and growth pattern phenotype of 30 GLUT-DS patients.

SUBJECTS/METHODS: An assessment was made of body weight (BW), body length/height (BL, BH) and body composition by anthropometry and DEXA, and the results put with BL and BW at birth, genetic target, glycemia, insulinemia, and glycorrhachia values.

RESULTS

At birth, 21% of patients had a BW below -1.645 z-score, whereas no patients had BL below the reference values. At diagnosis 23% of the patients had an impaired nutritional status, 19.2% and 3.8% being respectively underweight and overweight/obese; 10%, all under 10 years old, had BL/BH below -1.645 z-score, with no specific features related to body composition. Finally, there was no association between glycemia, glycorrhachia, and growth phenotype.

CONCLUSIONS

GLUT1-DS is associated with impaired BW but not BL intrauterine growth, with a slower than normal pattern of growth rather than growth failure. These data could be useful for the interpretation of any long-term effects of the ketogenic diet, e.g. nutritional and growth pattern decline.