Prevalence
The TPI-deficiency (triosephosphate isomerase deficiency) is rare. Its prevalence is unknown; however, less than 100 cases were described worldwide.
Clinical characteristics
The main clinical features are haemolytic anaemia, jaundice, progressive neuromuscular dysfunction, respiratory problems, and increased susceptibility to infection resulting in severe disease and death in early childhood. The symptoms depend on the type of the mutation (it is crucial!); some of them causes mild symptoms, mostly haemolytic anaemia.
Molecular characteristics
The most common and also the most fatal mutation is the Glu104Asp (Glu105Asp if the first Met is counted) caused by a G-C transversion in codon 104, which is responsible at least half of the recognized cases.
Genetic Counselling
Only homozygotes and compound heterozygotes are ill. Thus, if both parents are heterozygous, the risk increases, even if they carry different mutations. Low TPI enzyme activity (50% of the normal or less) can be indicative for heterozygote parents.
Management
Treatment is only symptomatic.
TPI1