It is tempting to speculate that this variant might represent the first example of incomplete penetrance for “SOX4-related disorders”, a phenomenon already observed for other disorders caused by variants of SOX genes, such as SOX9-associated campomelic dysplasia and sex reversal [20,21,22], SOX11-associated coloboma [23], and SOX5-associated Lamb–Shaffer syndrome [24]. The gene discussed is SOX9; the disease is campomelic dysplasia.