Moreover, the clinical phenotype and T-cell survival/function were improved by S-adenosylmethionine (SAM) and NR co-administration for patients with phosphoribosyl pyrophosphate synthetase 1 (PRPS1) deficiency (Arts syndrome, manifested by serious neurological and immunological deficiencies especially in males) [44]. The gene discussed is PRPS1; the disease is Lethal ataxia with deafness and optic atrophy.