Congenital hypothyroidism refers to the insufficient thyroid hormone among newborns possibly related to organ defect or problems with thyroid metabolism. The nurse should be concerned about the newborn patient who rarely cries and is always asleep. Other clinical features of hypothyroidism include coarse facial features, large fontanelles, umbilical hernia, and dry skin. Failure to thrive is unlikely given his normal body weight. Phenylketonuria is a metabolic condition characterized by seizures and neurological changes, while major depression is least likely to be among the newborns.