Complex sentence: The defect is a type of purine nucleoside phosphorylase deficiency with inactive phosphorylase, this results in an accumulation of deoxy-GTP which inhibits ribonucleotide reductase.
Split into simpler sentences: The defect is a type of purine nucleoside phosphorylase deficiency with inactive phosphorylase. This results in an accumulation of deoxy-GTP which inhibits ribonucleotide reductase.