Among 44 newborns, 7 were identified with homozygous mutations, 35 newborns had compound heterozygous mutations, and no mutation in SLC22A5 gene was detected in two newborns, but under the condition of full feeding and ruling out secondary carnitine deficiency, C0 < 10 μmol/L was detected for 3 consecutive times, accompanied by various acylcarnitine reductions, and finally diagnosed with PCD. Here, SLC22A5 is linked to systemic primary carnitine deficiency disease.