Congenital adrenal hyperplasia (CAH) is primarily caused by 21-hydroxylase deficiency and leads to an accumulation of 17-hydroxyprogesterone and reduced cortisol levels. Newborn screening for CAH is traditionally based on measuring 17-hydroxyprogesterone by different immunoassays. Despite attempts to adjust cutoff levels for birth weight, gestational age, and stress factors, the positive predictive value for CAH screening remains less than 1%. To improve this situation, we developed a method using liquid chromatography-tandem mass spectrometry to measure 17-hydroxyprogesterone, androstenedione, and cortisol simultaneously in blood spots. A total of 1222 leftover blood spots from six different screening programs using different immunoassays (fluorescent immunoassay and ELISA) were reanalyzed in a blinded fashion by liquid chromatography-tandem mass spectrometry. Thirty-one samples were from babies with CAH, 190 had yielded false-positive results by immunoassay, and the remaining 1001 samples were from babies with normal screening results. Steroid profiling allowed for an elimination of 169 (89%) of the false-positive results and for an improvement of the positive predictive value from the reported 0.5 to 4.7%. Although this method is not suitable for mass screening due to the length of the analysis (12 min), it can be used as a second-tier test of blood spots with positive results for CAH by the conventional methods. This would prevent unnecessary blood draws, medical evaluations, and stress to families.
Fetal and neonatal hyperthyroidism are usually produced by transplacental passage of thyroid-stimulating immunoglobulins. Most commonly, the thyroid-stimulating immunoglobulins are a component of active maternal Graves' disease. However, such antibodies may continue to be produced after ablation of the thyroid by surgery, radioiodine, or by the immune mechanisms of Hashimoto's thyroiditis. Other mechanisms that have produced fetal and neonatal hyperthyroidism include activating mutations of the stimulatory G protein in McCune-Albright syndrome and activating mutations of the thyrotropin (TSH) receptor. Fetal hyperthyroidism may be associated with intrauterine growth retardation, nonimmune fetal hydrops, craniosynostosis, and intrauterine death. Features of this condition in the neonate include hyperkinesis, diarrhea, poor weight gain, vomiting, ophthalmopathy, cardiac failure and arrhythmias, systemic and pulmonary hypertension, hepatosplenomegaly, jaundice, hyperviscosity syndrome, thrombocytopenia, and craniosynostosis. The time course of thyrotoxicosis depends on etiology. Remission by 20 weeks is most common in neonatal Graves' disease; remission by 48 weeks is nearly always seen. A subset of these patients may have persistent disease when there is a strong family history of Graves' diseases. Disease persistence is characteristic of patients with activating mutations of the TSH receptor. Treatment of fetal hyperthyroidism comprises administration of antithyroid drugs to the mother. Fetal heart rate and fetal growth should be monitored. Ultrasonography may reveal changes in thyroid size. At times, cordocentesis may be useful for monitoring fetal thyroid function. Hyperthyroid neonates may be treated with antithyroid drugs, beta-adrenergic receptor blocking agents, iodine, or iodinated contrast agents, and at times, with glucocorticoids and digoxin. Nonremitting causes of neonatal hyperthyroidism require ablative treatments such as thyroidectomy.
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