Alleles for a particular phenotype determine what characteristic an organism will express, as with the following example where. 1  Chromosome 1 contains an allele for blonde hair. 2  Chromosome 2 contains an allele for brown hair. 3  Chromosome 3 contains an allele for blue eyes. 4  Chromosome 4 contains an allele for brown eyes.
Because of the patient's smoking history and abnormal chest radiograph, a neoplasm was initially suspected as a cause of SIADH. The head trauma was too remote to be of concern. Although 1 case of risperidone-associated hyponatremia has been reported, the risk seems low with this agent and with olanzapine.
Hyponatremia associated with diuretics can be associated with overt clinical or physiologic evidence of hypovolemia. Since evidence of hypovolemia might be subtle, studies to define physiologic evidence of hypovolemia, such as measurement of the renin angiotensin system, can help differentiate the various causes of hyponatremia.