Pentosuria is a clinically benign autosomal recessive inborn error of metabolism seen in the Ashkenazi Jewish population caused by a defect in L-xylulose reductase (DCXR). This enzyme is responsible for converting L-xylulose to xylitol, and defects in function lead to high urinary excretion of L-xylulose.  Pierce et al. (PNAS 2011 Nov 8;108(45):18313-7) found two common mutations  in the DCXR gene via sequencing of multiple affected individuals: DCXR c.583deltaC and DCXRc.52(+1)G>A. The combined allele frequency in the Ashkenazu Jewish controls was 0.0173. This paper gives an interesting historical perspective on this pentosuria. 

Hilary Vernon, MD PhD

http://dx.doi.org/10.1036/ommbid.92 http://dx.doi.org/10.1036/ommbid.92