Individuals with complete ALS deficiency (ACLSD, OMIM #615961) have mutations in the IGFALS gene and exhibit severely reduced serum IGF1 and IGFBPs (particularly IGFBP3), leading to low birth weight and length, reduced head circumference and height, pubertal delay, and insulin resistance15–17. Here, IGFBP3 is linked to short stature due to primary acid-labile subunit deficiency.