Given that all ATR–SS patients to date share consanguinity, there are limitations in defining the spectrum of clinical features conferred by ATR deficiency to support a clinical distinction between ATR–SS and related disorders such as MOPD type II and MGS as well as other sub-classes of SS [1]–[3], [31]. The gene discussed is ATR; the disease is microcephalic osteodysplastic primordial dwarfism type II.