Previous research has identified issues such as cysteine deficiency (Ferrario et al. 2015), weak cell wall protease activity (Bottari et al. 2017), lack of amino acid transporters (Zafar and Saier Jr. 2022), and growth inhibition by hydrophobic amino acids (Gu et al. 2024). Here, SLC38A7 is linked to hyperinsulinemic hypoglycemia, familial, 4.