In the two genomic instability syndromes caused by mutations in non‐SMC elements of SMC5/6, the NSMCE2 mutations cause primordial dwarfism, extreme insulin resistance and gonadal failure,4 whereas the NSMCE3 mutations lead to lung disease immunodeficiency and chromosome breakage syndrome in early childhood.5 Here, NSMCE3 is linked to isolated growth hormone deficiency type IA.