BGLAP and sickle cell disease: Patients with sickle cell disease displayed the lowest levels of osteocalcin (45.6±17.6 ng/ml), which were significantly lower than those observed in healthy controls (115.3±35.2 ng/ml), (P<0.001, Mann-Whitney-U test with Bonferroni-Holm correction for multiple testing) and in patients with spherocytosis (90.0±46.7 ng/ml), (P = 0.015, Mann-Whitney test with Bonferroni-Holm correction for multiple testing) Figure 3.