We performed a proband-only exome and detected two homozygous mutations in two different genes: MAN2B1 (Mannosidase Alpha Class 2B Member 1) and SLC7A7 (Solute Carrier Family 7 Member 7), in which mutations cause alpha-mannosidosis and lysinuric protein intolerance respectively. The gene discussed is SLC7A7; the disease is alpha-mannosidosis.