This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
A baby boy is brought to the hospital because of convulsion. In the course of work up his body temperature & plasma glucose are normal but his CSF glucose is 12 mg/ dl. A possible explanation is 
Select and explain. 
A. SGLT 1 deficiency in astrocytes, B. GLUT 5 deficiency in cerebral capillaries, C. GLUT-1 55 K deficiency in capillaries, D. GLUT-1 45 K deficiency in microglia
C: GLUT-1 55 K deficiency in capillaries
Answer: C: GLUT-1 55 K deficiency in capillaries 
Explanation: Ans: c (GLUT 1 55K deficiency in capillaries) Ref: Ganong, 22nd ed, p. 615It is a direct pick from self study MCQs in Ganong.According to the given parameters there is deficient transport of glucose across brain capillaries.The predominant GLUT in the brain is GLUT-1 55 K (Ganong p. 615). GLUT-1 45 K is also present in brain capillaries and not in microglia.GLUT 1 - RBC, brain, kidney, placenta, retinaGLUT 2 - Liver, B cells of pancreasGLUT 3 - BrainGLUT 4 - Skin, cardiac muscle, adipose tissueGLUT 5 - Testes, spermsGLUT 7 - Liver, endoplasmic reticulumNote:GLUT 4 is mediated by insulin.GLUT 5 is used as a fructose transporter (semen).