<unk>  is an autosomal recessive congenital immunodeficiency condition due to underdevelopment of the thymus. 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. Ribonucleotide reductase catalyzes the formation of deoxyribonucleotides from ribonucleotides, thus, DNA replication is inhibited.
Nezelof syndrome
Helsmoortel-Van der Aa syndrome
Pretzel syndrome
Van der Woude syndrome
Wildervanck syndrome
Rapunzel syndrome
Van Wyk and Grumbach syndrome
Stewart–Treves syndrome