ALB and rickets: Since serum albumin was significantly lower in those with significant proteinuria, it may be that urinary loss of albumin with vitamin D bound to it is the main mechanism to explain hypovitaminosis D. The reason for low DBP in almost all AL patients requires further investigation but given that it has a molecular weight of 52-59 kDa, which is slightly lower than that of albumin (66.5 kDa), it is likely that increased urinary losses are a major contributing factor.