PIK3R1 and SHORT syndrome: Finally, there is PIK3R1, a gene involved in the PI3K/AKT/mTOR pathway, which promotes cell proliferation and survival [91]; heterozygous mutations in PIK3R1 cause the so-called SHORT syndrome, characterized by short stature (S), hyperextensibility of joints and/or inguinal hernia (H), ocular depression (O), Rieger abnormality (R) and teething delay (T) [92].