Consistent with this finding, functional data demonstrate absence of the OCRL1 mRNA or a total or near-total lack of 5-phosphatase activity in Lowe syndrome patients.10,32 Conversely, DD2 patients harbor missense mutations in this same region of OCRL1, yielding protein products with reduced 5-phosphatase activity, or early truncating mutations in exons 1–7.3 It is worth noting that early truncating mutations in OCRL1 often produce clinically mild DD2. The gene discussed is OCRL; the disease is oculocerebrorenal syndrome.