Genetic DPD deficiency leads to disorders of the pyrimidine metabolism. Patients with two pathogenic variants in both alleles of the DPYD gene in combined heterozygous or homozygous form often present with developmental disorders, seizures, short stature, microcephaly, dysmorphia and autistic behaviors. A clear genotype-phenotype correlation has not yet been demonstrated, as the expression of symptoms in patients described in the literature varies widely. To date, the underlying pathomechanism of the syndrome has also not been clearly clarified. Thymine uraciluria specifically indicates DPD deficiency by laboratory diagnostics.
In patients with this syndrome, chemotherapy with 5-fluorouracil (5-FU) and its prodrugs is contraindicated.
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