Combined Gestational Age- and Birth Weight-Adjusted Cutoffs for Newborn Screening of Congenital Adrenal Hyperplasia.

CONTEXT: Congenital adrenal hyperplasia (CAH) was among the first genetic disorders included in newborn screening (NBS) programs worldwide, based on 17α-hydroxyprogesterone (17-OHP) levels in dried blood spots. However, the success of NBS for CAH is hampered by high false positive (FP) rates, especially in preterm and low-birthweight infants. OBJECTIVE: To establish a set of cutoff values adjusting for both gestational age (GA) and birthweight (BW), with the aim of reducing FP rates. DESIGN: This cross-sectional, population-based study summarizes 10 years of experience of the Israeli NBS program for diagnosis of CAH. Multitiered 17-OHP cutoff values were stratified according to both BW and GA. PARTICIPANTS: A total of 1,378,132 newborns born between 2008 and 2017 were included in the NBS program. RESULTS: Eighty-eight newborns were ultimately diagnosed with CAH; in 84 of these, CAH was detected upon NBS. The combined parameters-adjusted approach significantly reduced the recall FP rate (0.03%) and increased the positive predictive value (PPV) (16.5%). Sensitivity among those referred for immediate attention increased significantly (94%). There were four false negative cases (sensitivity, 95.4%), all ultimately diagnosed as simple-virilizing. Sensitivity and specificity were 95.4% and 99.9%, respectively, and the percentage of true-positive cases from all newborns referred for evaluation following a positive NBS result was 96%. CONCLUSIONS: The use of cutoff values adjusted for both GA and BW significantly reduced FP rates (0.03%) and increased overall PPV (16.5%). Based on our 10 years of experience, we recommend the implementation of this two parameter-adjusted approach for NBS of classic CAH in NBS programs worldwide.

Clinical and genetic heterogeneity of congenital adrenal hypoplasia due to NR0B1 gene mutations.

INTRODUCTION: X-linked adrenal hypoplasia congenita (AHC) is a rare disorder caused by mutations or complete deletion of the NR0B1 gene that encodes the DAX-1 protein, an orphan member of the nuclear receptor superfamily. AHC is characterized by adrenal insufficiency in infancy and early childhood. Later, hypogonadotropic hypogonadism (HH) manifests as pubertal failure. PATIENTS AND METHODS: We evaluated the clinical, endocrine and molecular characteristics of 12 AHC patients from 5 families diagnosed between 1984 and 2007 in Israel. RESULTS: Most of the boys (10/12) presented with signs of adrenal insufficiency such as salt wasting and failure to thrive during the neonatal period. Aldosterone deficiency usually preceded cortisol deficiency requiring early mineralocorticoid therapy. Serum cortisol levels in the first weeks of life varied from very low to high levels (<2.76 to >1776 nmol/l). Five boys showed signs of precocious sexual development during infancy and childhood, including enlargement of the penis and testes. In four patients the initial diagnoses were erroneous. Molecular analysis of the NR0B1 gene identified point mutations in six patients including a novel splice site mutation in one patient and his family (IVS1-1G-->C). Contiguous gene deletion was found in six patients from two families who manifested impaired mental development. CONCLUSIONS: In X-linked AHC caused by different molecular defects in NR0B1 gene, the clinical spectrum of the disease is quite variable and precocious sexual development is a prominent feature. Genetic testing is indicated in boys presenting with salt-wasting with or without cortisol deficiency if congenital adrenal hyperplasia has been ruled out.

Hypothyroidism and dyshormonogenesis induced by D-penicillamine in children with Wilson's disease and healthy infants born to a mother with Wilson's disease.

Two siblings born to a mother with Wilson's disease, who was taking D-penicillamine, developed transient goitrous hypothyroidism. A prospective evaluation of 5 patients with Wilson's disease taking and not taking D-penicillamine for as long as 9.5 years showed subclinical hypothyroidism. D-penicillamine probably inhibited thyroperoxidase activity in utero in healthy infants and during childhood in patients with Wilson's disease.

Early blood thyroxine concentration and necrotizing enterocolitis in premature infants.

OBJECTIVES: To determine the association between the first thyroxine blood concentration and necrotizing enterocolitis (NEC) among preterm infants. STUDY DESIGN: The study group included a cohort of 34 preterm infants with NEC developed at least 48 h after thyroid function screening was obtained. The control group was consisted of 102 preterm infants (3 infants for each infant with NEC, born at the same gestational age) without NEC. Clinical data and first filter paper of total blood thyroxine concentration taken in the first 2 weeks of life were recorded retrospectively and compared between the study and control groups. RESULTS: Mean filter paper total thyroxine concentration was slightly lower in the study group compared to the control group (86.2 nmol/L and 97.8 nmol/L, respectively) but did not reach statistical significance (p=0.14). Nine infants (26.5%) in the study group were small for gestational age (SGA) in comparison to 11 infants (10.8%) in the control group (p=0.07). CONCLUSIONS: It seems that the first thyroxin serum concentration is not a significant predisposing risk factor for NEC in preterm infants.

Gestational exposure to high perchlorate concentrations in drinking water and neonatal thyroxine levels.

OBJECTIVE: To assess the effect of gestational perchlorate exposure through drinking water on neonatal thyroxine (T(4)). DESIGN: T(4) values were compared among newborns in Ramat Hasharon, Israel, whose mothers resided in suburbs where drinking water contained perchlorate < or = 340 microg/L (very high exposure, n = 97), 42-94 microg/L (high exposure, n = 216), and < 3 microg/L (low exposure, n = 843). In the very high and high exposure areas, T(4) values in newborns whose mothers drank tap water exclusively (as determined by a telephone interview) were analyzed as a subset. Serum perchlorate levels in blood from donors residing in the area were used as proxy indicators of exposure. MAIN OUTCOME: Neonatal T(4) values (mean +/- SD) in the very high, high, and low exposure groups were 13.9 +/- 3.8, 13.9 +/- 3.4, and 14.0 +/- 3.5 microg/dL, respectively (p = NS). Serum perchlorate concentrations in blood from donors residing in areas corresponding to these groups were 5.99 +/- 3.89, 1.19 +/- 1.37, and 0.44 +/- 0.55 microg/L, respectively. T(4) levels of neonates with putative gestational exposure to perchlorate in drinking water were not statistically different from controls. CONCLUSION: This study finds no change in neonatal T(4) levels despite maternal consumption of drinking water that contains perchlorate at levels in excess of the Environmental Protection Agency (EPA) drinking water equivalent level (24.5 microg/L) based on the National Research Council reference dose (RfD) [0.7 microg/(kg.day)]. Therefore the perchlorate RfD is likely to be protective of thyroid function in neonates of mothers with adequate iodide intake.

Clinical and genetic characteristics of congenital hypothyroidism due to mutations in the thyroid peroxidase (TPO) gene in Israelis.

OBJECTIVES: Iodide organification defect (IOD) is characterized by a reduced ability of the thyroid gland to retain iodide and results in hypothyroidism. Mutations in the thyroid peroxidase (TPO) gene are a frequent cause of IOD. While TPO mutations have been identified in various populations, none have been reported in Israeli patients with IOD. The objectives of this study were to characterize the molecular basis of IOD in an Israeli Arab-Muslim population and to analyse the clinical, neurological and imaging data of patients with TPO mutations followed for up to 29 years. PATIENTS: Twenty-two patients from six core families with congenital hypothyroidism (CH) and IOD living in the same region. DESIGN AND MEASUREMENTS: All subjects underwent clinical, hormonal and imaging evaluation. The TPO gene was directly sequenced and the presence of specific mutations among family members was determined by restriction fragment length polymorphism (RFLP). RESULTS: All patients had congenital and persistent primary hypothyroidism. The thyroid gland was demonstrated in all subjects by technetium (99mTc) scans. A positive perchlorate discharge test (mean 87%) was indicative of IOD. Enlargement of the thyroid gland was shown in 64% of our patients, mostly with multinodular appearance, and in some with retrosternal invasion. Neurological complications were observed in 13 patients (59%). Four subjects, who carry two different TPO mutations, had sensorineural deafness. Two previously described TPO gene mutations [G1567A (G493S) and C1708T (R540X)] and one novel TPO gene mutation [C965T (S292F)] were identified. The two previously described mutations were present in 90% of the subjects. Haplotyping suggested a distant common ancestry for each of these two mutations. CONCLUSIONS: Three different TPO gene mutations were found to be responsible for IOD in a consanguineous Israeli population. The high rate of development of multinodular glands (MNGs) in our cohort of patients indicates the need for long-term follow-up of patients with TPO gene mutations.

Somatostatin treatment of congenital chylothorax may induce transient hypothyroidism in newborns.

AIM: To describe a group of neonates with congenital, non-traumatic chylothorax, one of whom developed transient hypothyroidism following treatment with somatostatin. METHODS: The charts of seven infants with congenital chylothorax were reviewed in terms of their clinical presentation, the severity of their disease, the complications they presented and the duration of their hospitalization. Their pituitary-thyroid axis function was monitored in particular. RESULTS: The seven infants, all preterm (32-34 wk), suffered from congenital chylothorax and hydrops fetalis diagnosed during the prenatal period. Four were treated by intrauterine drainage, and four had congenital malformations. Hospitalization lasted from 32 to 120 d. Three of the infants suffered from thrombocytopenia, three had chronic lung disease, and one suffered from Gram-negative sepsis. The infant treated with somatostatin initially had normal thyroid function, but later developed primary transient hypothyroidism and was treated with L-thyroxine. The thyroid screening tests for the infants who were not treated with somatostatin were all normal. CONCLUSIONS: Repeated doses of somatostatin were effective in reducing chylus production. Administering this treatment earlier should be considered in order to minimize known complications. The only potential side effect observed was primary transient hypothyroidism. Therefore, careful monitoring of the pituitary-thyroid axis is advised.

Diversity and function of mutations in p450 oxidoreductase in patients with Antley-Bixler syndrome and disordered steroidogenesis.

P450 oxidoreductase (POR) is the obligatory flavoprotein intermediate that transfers electrons from reduced nicotinamide adenine dinucleotide phosphate (NADPH) to all microsomal cytochrome P450 enzymes. Although mouse Por gene ablation causes embryonic lethality, POR missense mutations cause disordered steroidogenesis, ambiguous genitalia, and Antley-Bixler syndrome (ABS), which has also been attributed to fibroblast growth factor receptor 2 (FGFR2) mutations. We sequenced the POR gene and FGFR2 exons 8 and 10 in 32 individuals with ABS and/or hormonal findings that suggested POR deficiency. POR and FGFR2 mutations segregated completely. Fifteen patients carried POR mutations on both alleles, 4 carried mutations on only one allele, 10 carried FGFR2 or FGFR3 mutations, and 3 patients carried no mutations. The 34 affected POR alleles included 10 with A287P (all from whites) and 7 with R457H (four Japanese, one African, two whites); 17 of the 34 alleles carried 16 "private" mutations, including 9 missense and 7 frameshift mutations. These 11 missense mutations, plus 10 others found in databases or reported elsewhere, were recreated by site-directed mutagenesis and were assessed by four assays: reduction of cytochrome c, oxidation of NADPH, support of 17alpha-hydroxylase activity, and support of 17,20 lyase using human P450c17. Assays that were based on cytochrome c, which is not a physiologic substrate for POR, correlated poorly with clinical phenotype, but assays that were based on POR's support of catalysis by P450c17--the enzyme most closely associated with the hormonal phenotype--provided an excellent genotype/phenotype correlation. Our large survey of patients with ABS shows that individuals with an ABS-like phenotype and normal steroidogenesis have FGFR mutations, whereas those with ambiguous genitalia and disordered steroidogenesis should be recognized as having a distinct new disease: POR deficiency.

Postpartum maternal hyperthyrotropinemia in an area in which iodine supplementation is required.

Mild maternal hypothyroidism during pregnancy can adversely affect infant development. We studied thyrotropin (TSH) levels in mothers of premature and low-birth-weight infants in Colombia, where iodized salt supplements the diet to correct iodine deficiency. The additional impact of salt restriction in mothers with hypertensive disorders was examined. Blood was spotted on filter paper from 404 mothers and their infants. Using radioimmunoassay (RIA), TSH was measured in the mothers, and TSH and thyroxine in their infants at three postpartum times. Initially, mothers had high TSH levels (i.e., TSH > 10 mU/L in half the mothers at the first assessment). Fourteen days later, only 9.3%, and at calculated term 7.5% were greater than 10 mU/L. Maternal TSH levels correlated with infant birth weight and gestational age (r = 0.47, and r = 0.49, p < 0.01). Initial TSH values were higher in salt restricted (20.1 +/- 2 mU/L, n = 76) versus control mothers (14.6 +/- 0.85, n = 328, p < 0.01), dropping dramatically in both groups 14 days later (to 3.4 +/- 0.7 mU/L vs. 2.8 +/- 0.4 mU/L) and at calculated term (2.8 +/- 0.4 mU/L vs. 2.3 +/- 0.6 mU/L). Increased maternal TSH levels during pregnancy in an iodine-deficient area may be aggravated by salt restriction. Monitoring TSH and supplementing iodine or thyroxine are recommended in pregnancy, especially if dietary salt restriction is prescribed.

Transient elevation of triiodothyronine caused by triiodothyronine autoantibody associated with acute Epstein-Barr-virus infection.

A unique 16-year old female patient presented after acute Epstein-Barr virus (EBV) infection with severe primary hypothyroidism. Her thyroid test results were thyrotropin level (TSH) of 198 mU/L (normal, 0.4-4 mU/L), free thyroxine [FT(4)], 2.5 pmol/L (normal, 10-25 pmol/L), total triiodothyronine (TT(3)) > 19.5 nmol/L (normal, 1.3-2.7 nmol/L), and free triiodothyronine (FT(3)), 0.77 pmol/L (normal, 3.3-6.3 pmol/L). She had high titers of thyroglobulin and thyroid peroxidase autoantibodies. In vitro triiodothyronine (T(3))-binding measured by radioimmunoprecipitation was 86% (normal, up to 8.5%) and thyroxine (T(4))-binding 8.2% (normal, 6.4%). Serum immunoglobulin G (IgG) absorption, achieved by protein-G Sepharose beads, decreased TT(3) toward normal. Levothyroxine treatment normalized the low baseline FT(4) and FT(3) values, and suppressed TSH to normal. However, TT(3) remained highly elevated and returned to normal after 20 months, while T(3 )binding gradually decreased. Thus, her severe hypothyroidism was masked by this unusual phenomenon. Thirty-four patients with EBV infection (15 with acute disease and 19 with previous infection) were tested for thyroid hormone levels. EBV antibodies (early antigen immunoglobulin M [IgM] and IgG and anti-Epstein-Barr virus nuclear antigen [EBNA] IgG) were measured by enzyme-linked immunosorbent assay (ELISA). In 15 patients with acute EBV the mean TT(3) level was 2.47 +/- 0.39 nmol/L (5 had TT(3) values above normal) compared to a mean TT(3) of 1.70 +/- 0.53 nmol/L in 19 subjects with previous infection (p < 0.0005; only 1 had a TT(3) result above normal), with no differences in FT(4) and TSH concentrations between the two groups. Acute EBV infection may be associated with transient mild to severe TT(3) elevation as a result of assay interference by anti-T(3) autoantibodies.

Thyroid function in pregnancy - maternal-fetal relationship in health and disease.

The article reviews the changes in maternal and fetal thyroid function during pregnancy. During the first trimester the fetus is dependant on maternal thyroxine and later on the direct supply of iodine from the mother for its own thyroxine production. The placental deiodinase metabolism provides the fetus with additional iodine and protects the fetus from excessive iodothyronine transfer and enables the development of its own hypothalamic pituitary thyroid axis. Maternal and fetal hypothyroxinemia can lead to irreversible CNS damage. In autoimmune thyroid diseases immunoglobulins and goitrogenic drugs can cross the placenta and affect the fetal thyroid. Therefore, careful monitoring of maternal iodine supply, even in areas with mild to moderate iodine deficiency as well as iodine FT4 before and during pregnancy, and avoidance of unnecessary goitrogenic drugs is mandatory for optimal fetal growth and development. In cases where fetal hypothyroidism is diagnosed, intraamniotic T4 treatment is suggested.

Protein tyrosine phosphatase activity in insulin-resistant rodent Psammomys obesus.

Phosphotyrosine phosphatase (PTPase) activity and its regulation by overnight food deprivation were studied in Psammomys obesus (sand rat), a gerbil model of insulin resistance and nutritionally induced diabetes mellitus. PTPase activity was measured using a phosphopeptide substrate containing a sequence identical to that of the major site of insulin receptor (IR) beta-subunit autophosphorylation. The PTPase activity in membrane fractions was 3.5-, 8.3-, and 5.9-fold lower in liver, fat, and skeletal muscle, respectively, compared with corresponding tissues of albino rat. Western blotting of tissue membrane fractions in Psammomys showed lower PTPase and IR than in albino rats. The density of PTPase transmembrane protein band was 5.5-fold lower in liver and 12-fold lower in adipose tissue. Leukocyte antigen receptor (LAR) and IR were determined by specific immunoblotting and protein bands densitometry and were also found to be 6.3-fold lower in the liver and 22-fold lower in the adipose tissue in the hepatic membrane fractions. Liver cytosolic PTPase activity after an overnight food deprivation in the nondiabetic Psammomys rose 3.7-fold compared with postprandial PTPase activity, but it did not change significantly in diabetic fasted animals. Similar fasting-related changes were detected in the activity of PTPase derived from membrane fraction. In conclusion, the above data demonstrate that despite the insulin resistance, Psammomys is characterized by low level of PTPase activities in membrane and cytosolic fractions in all 3 major insulin responsive tissues, as well as in liver. PTPase activity does not rise in activity as a result of insulin resistance and nutritionally induced diabetes.

Longitudinal assessment of pituitary-thyroid axis and adrenal function in preterm infants raised by 'kangaroo mother care'.

OBJECTIVE: To assess whether complete kangaroo mother care (KMC), a skin-to-skin contact intervention, would affect longitudinal/developmental patterns of hormonal change. METHOD: An open randomized controlled trial was conducted in a large tertiary care hospital, comparing KMC and traditional care for newborn infants weighing less than 2,001 g. Eighty-seven healthy preterm (<37 weeks gestational age) infants from this study provided three blood-spot samples on filter paper: at randomization (postnatal age 1-5 days), 2 weeks later, and at calculated term (41 weeks gestational age). They met a number of additional inclusion criteria including discharge from the hospital within the first postnatal week. The levels of 17alpha-hydroxy-progesterone (17-OHP), thyroxine-stimulating hormone (TSH) and thyroxine (T(4)) were assessed by radioimmunoassay. Birth weight (<1,800 or > or =1,800 g) and prenatal maternal corticosteroid treatment were taken into account in the analysis. INTERVENTIONS: Complete KMC includes early discharge, positioning the infant on the parent's chest in an upright position, 24 h/day in skin-to-skin contact, and breast-feeding. In the traditional care group, infants were discharged according to routine hospital practice. RESULTS: Levels of 17-OHP and TSH decreased significantly from eligibility to calculated term while T(4) levels did not change significantly over time. Most importantly, overall, treatment (KMC) did not interact with the pattern of physiological change. CONCLUSIONS: Maturation of the pituitary-thyroid axis and adrenal function is apparently not compromised by KMC, at least in healthy preterm infants.