RPI Deficiency: A brief overview
- RPI deficiency. Ribose-5-phosphate isomerase deficiency is a human disorder caused by mutations in the pentose phosphate pathway enzyme ribose-5-phosphate isomerase.
- With only three diagnosed patients over a 27-year period, RPI deficiency is currently the rarest disease in the world.
- In the case of this disorder, RPI functions partially in tissues, because if the gene was simply non-functional, it would likely be lethal. This means that a specific type of mutation needs to occur for this disorder to occur.
- Symptoms:- optic atrophy, nystagmus, cerebellar ataxia, seizures, spasticity, psychomotor retardation, leukoencephalopathy and global developmental delay.
FURTHER ANALYSIS:-
The present
article describes the first patient with a deficiency of ribose-5-phosphate
isomerase (RPI) (Enzyme Commission number 5.3.1.6) 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.
Because of the biochemical
findings, we decided to sequence the gene RPI. cDNA was synthesized from total RNA derived
from lymphoblast’s of the patient by Omni script Transcriptase (RT) (Qiagen).
TREATMENT:- No such particular type of treatment method is discovered yet but the disease can be detected by some medicinal tests like MRI and further medications has been done by the concerned specialist.
RPI ( Ribulose 5 phosphate isomerase molecular structure)
(Source: NCBI. NORD, OMIM)
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