Hörster et al. [9] reported that their cohort of patients with mut0 (n = 42) and Cbl-B (n = 11) exhibited higher MMA excretion and an earlier onset of symptoms, a higher frequency of complications and deaths, and more frequent CKD (61% and 66%, respectively), which was predicted according to their urinary MMA levels, while better outcomes in mut- forms were observed by Liang et al., who reported that only 22 of 365 patients with such mutations had CKD [10]. The gene discussed is CBLB; the disease is chronic kidney disease.