Inherited mutations in the FAR1 gene causing reduction or complete loss of FAR1 activity result in peroxisomal FAR1 deficiency (MIM #616154, also referred to as RCDP type 4), which can be clinically distinguished from the other forms of RCDP by the absence of chondrodysplasia punctata or rhizomelia (Buchert et al., 2014; Alshenaifi et al., 2019). Here, FAR1 is linked to hyperinsulinemic hypoglycemia, familial, 4.