Ribose-5-Phosphate Isomerase Deficiency: New Inborn Error in the Pentose Phosphate Pathway Associated with a Slowly Progressive Leukoencephalopathy

Jojanneke H.J. Huck, Nanda M. Verhoeven, Eduard A. Struys, Gajja S. Salomons, Cornelis Jakobs, Marjo S. Van Der Knaap*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


The present article describes the first patient with a deficiency of ribose-5-phosphate isomerase (RPI) (Enzyme Commission number who presented with leukoencephalopathy and peripheral neuropathy. Proton magnetic resonance spectroscopy of the brain revealed highly elevated levels of the polyols ribitol and D-arabitol, which were subsequently also found in high concentrations in body fluids. Deficient activity of RPI, one of the pentose-phosphate-pathway (PPP) enzymes, was demonstrated in fibroblasts. RPI gene-sequence analysis revealed a frame-shift and a missense mutation. Recently, we described a patient with liver cirrhosis and abnormal polyol levels in body fluids, related to a deficiency of transaldolase, another enzyme in the PPP. RPI is the second known inborn error in the reversible phase of the PPP, confirming that defects in pentose and polyol metabolism constitute a new area of inborn metabolic disorders.

Original languageEnglish
Pages (from-to)745-751
Number of pages7
JournalAmerican journal of human genetics
Issue number4
Publication statusPublished - Apr 2004

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