The natural history of dihydrolipoamide dehydrogenase deficiency in Israel.

Dihydrolipoamide dehydrogenase (DLD) deficiency is an ultra-rare autosomal-recessive inborn error of metabolism, affecting no less than five mitochondrial multienzyme complexes. With approximately 30 patients reported to date, DLD deficiency was associated with three major clinical presentations: an early-onset encephalopathic phenotype with metabolic acidosis, a predominantly hepatic presentation with liver failure, and a rare myopathic phenotype. To elucidate the demographic, phenotypic, and molecular characteristics of patients with DLD deficiency within the Israeli population, data were collected from metabolic disease specialists in four large tertiary medical centers in the center and south of Israel. Pediatric and adult patients with biallelic variants in DLD were included in the study. A total of 53 patients of 35 families were included in the cohort. Age at presentation ranged between birth and 10 years. Wide phenotypic variability was observed, from asymptomatic individuals in their sixth decade of life, to severe, neonatal-onset disease with devastating neurological sequelae. Six DLD variants were noted, the most common of which was the c.685G>T (p.G229C) variant in homozygous form (24/53 patients, 45.3%; 13/35 families), observed mostly among patients of Ashkenazi-Jewish descent, followed by the homozygous c.1436A>T (p.D479V) variant, found in 20 patients of Bedouin descent (37.7%; 16/35 families). Overall, patients did not necessarily present as one of the previously described distinct clinical phenotypes. DLD deficiency is a panethnic disorder, with significant phenotypic variability, and comprises a continuum, rather than three distinct clinical presentations.

Newborn screening algorithm distinguishing potential symptomatic isovaleric acidemia from asymptomatic newborns.

Newborn screening (NBS) for isovaleric acidemia (IVA) reduces mortality and morbidity; however, it has also resulted in the detection of individuals with an asymptomatic or mild presentation for which early detection via newborn screening has not been proven to alter neurological outcome. We reevaluated biochemical and molecular data for newborns flagged positive for IVA in aim of developing a new screening algorithm to exclude the latter from positive screening. Among 2 794 365 newborns underwent routine newborn screening in Israel, 412 flagged positive for IVA, of which, 371 were false positives on recall sample testing and 41 positive newborns were referred to the clinic. 38/41 have biochemical and molecular confirmation in keeping with IVA. Among the 38 patients, 32% (12/38) were classified as symptomatic while, 68% (26/38) were classified as asymptomatic. 69% of the latter group harbor the known variant associated with mild potentially asymptomatic phenotype, c.932C>T; p. Ala311Val. Among asymptomatic patients, only 46% (12/26) are currently treated. Two novel variants have been detected in the IVD gene: c.487G>A; p. Ala163Thr and c.985A>G; p. Met329Val. Cut-off recalculation, of referred newborns' initial biochemical results, after classifying the referred patients to two binary groups of symptomatic and asymptomatic, resulted in an improved NBS algorithm comprising of C5 >5 µM and C5/C2>0.2 and C5/C3>4 flagging only those likely to have the classic symptomatic phenotype.

A common benign intronic deletion masking a pathogenic deep intronic PCCB variant - genome sequencing and RNA studies to the rescue.

Propionic acidemia (PA) is an autosomal recessive metabolic disorder caused by variants in PCCA or PCCB, both sub-units of the propionyl-CoA carboxylase (PCC) enzyme. PCC is required for the catabolism of certain amino acids and odd-chain fatty acids. In its absence, the accumulated toxic metabolites cause metabolic acidosis, neurologic symptoms, multi-organ dysfunction and possible death. The clinical presentation of PA is highly variable, with typical onset in the neonatal or early infantile period. We encountered two families, whose children were diagnosed with PA. Exome sequencing (ES) failed to identify a pathogenic variant, and we proceeded with genome sequencing (GS), demonstrating homozygosity to a deep intronic PCCB variant. RNA analysis established that this variant creates a pseudoexon with a premature stop codon. The parents are variant carriers, though three of them display pseudo-homozygosity due to a common large benign intronic deletion on the second allele. The parental presumed homozygosity merits special attention, as it masked the causative variant at first, which was resolved only by RNA studies. Arriving at a rapid diagnosis, whether biochemical or genetic, can be crucial in directing lifesaving care, concluding the diagnostic odyssey, and allowing the family prenatal testing in subsequent pregnancies. This study demonstrates the power of integrative genetic studies in reaching a diagnosis, utilizing GS and RNA analysis to overcome ES limitations and define pathogenicity. Importantly, it highlights that intronic deletions should be taken into consideration when analyzing genomic data, so that pseudo-homozygosity would not be misinterpreted as true homozygosity, and pathogenic variants will not be mislabeled as benign.

Addition of galactose-1-phosphate measurement enhances newborn screening for classical galactosemia.

Galactosemia is an inborn disorder of carbohydrate metabolism of which early detection can prevent severe illness. Although the assay for galactose-1-phosphate uridyltransferase (GALT) enzyme activity has been available since the 1960s, many issues prevented it from becoming universal. In order to develop the Israeli newborn screening pilot algorithm for galactosemia, flow injection analysis tandem mass spectrometry measurement of galactose-1-phosphate in archived dried blood spots from newborns with classical galactosemia, galactosemia variants, epimerase deficiency, and normal controls, was conducted. Out of 431 330 newborns screened during the pilot study (30 months), two with classical galactosemia and four with epimerase deficiency were identified and confirmed. Five false positives and no false negatives were recorded. Following this pilot study, the Israeli final and routine newborn screening algorithm, as recommended by the Advisory Committee to the National Newborn Screening Program, now consists of galactose-1-phosphate measurement integrated into the routine tandem mass spectrometry panel as the first-tier screening test, and GALT enzyme activity as the second-tier performed to identify only newborns suspected to be at risk for classical galactosemia. The GALT enzyme activity cut-off used in the final algorithm was lowered in order to avoid false positives.

Preterm Singleton Birth Rate during the COVID-19 Lockdown: A Population-Based Study.

OBJECTIVE: The aim of the study is to evaluate the effect of the coronavirus disease 2019 (COVID-19) pandemic national lockdown period on the rate of singleton preterm births in Israel. STUDY DESIGN: This is a population-based cohort study of 3,41,291 singleton infants born in the months of January to July 2017 to 2020. Multivariable logistic regression analyses were used to estimate the influence of period and year on the rates of preterm births during the lockdown period (11th March - 5th May 2020) compared with rates before (January 1st 2020 - March 10th 2020), and after the lockdown (May 6th 2020-June 30th 2020) and to the corresponding periods in 2017to 2019. RESULTS: During the lockdown period the preterm birth rate (primary outcome) decreased by 9.7% from 5.05 to 4.56% in the pre-lockdown period (p = 0.006), an adjusted decrease of -0.52% (95% confidence interval -0.89%; -0.15%), odds ratio 0.898 (95% confidence interval 0.832; 0.970). CONCLUSION: The rate of singleton preterm births declined by 9.7% during the COVID-19 pandemic national lockdown period in Israel. KEY POINTS: · A 10% decline in all preterm deliveries was observed during the COVID-19 pandemic national lock-down period.. · The lock-down might influence environmental changes which contribute to the decrease in preterm deliveries.. · Changes in lifestyle, and societal behavior might contribute to the decrease in preterm deliveries..

Maternal iodine deficiency: a newborns' overweight risk factor? A prospective study.

OBJECTIVES: Childhood obesity and iodine deficiency are global public health concerns. Whether maternal iodine status mediates overweight in infancy has yet to be explored. We aimed to assess the relationship between maternal iodine status and infant birth weight, including small and large for gestational age (SGA and LGA, respectively). METHODS: A prospective study was carried out among 134 mother-infant pairs from Israel. Maternal iodine intake and status were estimated via questionnaire and serum thyroglobulin (Tg), respectively. Estimated iodine intake below the Recommended Daily Allowance for iodine sufficiency in pregnancy (220 µg/d) considered Inadequate. Maternal and neonatal thyroid function and anthropometric measurements, as well as maternal thyroid antibodies were also tested. RESULTS: After screening, 118 participants met the inclusion criteria (distributed trimesters I, II and III: n = 3, n = 21, and n = 94, respectively). There was a negative association of iodine intake with Tg values among the study population. Maternal median Tg value was higher than the sufficiency cutoff (16.5 vs 13 µg/L), indicating insufficient iodine status. No SGA cases were found. Inadequate iodine intake was associated with maternal isolated hypothyroxinemia (OR = 3.4; 95% CI 1.2, 9.9) and higher birthweight (including macrosomia and LGA) rates. A suggestive association of elevated Tg with a greater risk of LGA was observed. Offsprings' birth weight percentiles were associated with Tg values in pregnant women with suggestive sufficient iodine status (n = 62, R2 = 0.11, p < 0.05). CONCLUSIONS: Iodine status during pregnancy can be associated with newborn anthropometric index. Maternal inadequate iodine intake may alter fetal growth and might increase the risk of LGA among newborns. These initial findings support the need to further study the impact of iodine deficiency on newborns overweight in Israel and elsewhere.

The role of orotic acid measurement in routine newborn screening for urea cycle disorders.

Urea cycle disorders (UCDs), including OTC deficiency (OTCD), are life-threatening diseases with a broad clinical spectrum. Early diagnosis and initiation of treatment based on a newborn screening (NBS) test for OTCD with high specificity and sensitivity may contribute to reduction of the significant complications and high mortality. The efficacy of incorporating orotic acid determination into routine NBS was evaluated. Combined measurement of orotic acid and citrulline in archived dried blood spots from newborns with urea cycle disorders and normal controls was used to develop an algorithm for routine NBS for OTCD in Israel. Clinical information and genetic confirmation results were obtained from the follow-up care providers. About 1147986 newborns underwent routine NBS including orotic acid determination, 25 of whom were ultimately diagnosed with a UCD. Of 11 newborns with OTCD, orotate was elevated in seven but normal in two males with early-onset and two males with late-onset disease. Orotate was also elevated in archived dried blood spots of all seven retrospectively tested historical OTCD patients, only three of whom had originally been identified by NBS with low citrulline and elevated glutamine. Among the other UCDs emerge, three CPS1D cases and additional three retrospective CPS1D cases otherwise reported as a very rare condition. Combined levels of orotic acid and citrulline in routine NBS can enhance the detection of UCD, especially increasing the screening sensitivity for OTCD and differentiate it from CPS1D. Our data and the negligible extra cost for orotic acid determination might contribute to the discussion on screening for proximal UCDs in routine NBS.

Thyroid function tests in newborns of mothers with hypothyroidism.

Performing thyroid function tests (TFT) at 2 weeks of age in neonates of mothers with hypothyroidism, despite having a newborn screening program, is a debated approach. We examined whether there is an additional clinical benefit in TFT at 2 weeks of age in neonates born to mothers with hypothyroidism, in addition to the neonatal screening program. We performed a retrospective study which included all newborns of mothers with a diagnosis of hypothyroidism and gave birth in a single regional hospital between the years 2010 and 2016. Data were collected from a computerized medical record system of the hospital and the community clinics, and from Israel's national newborn screening program. Main outcome measure was results of serum TFT in comparison to the results of the neonatal screening test. There were 1392 newborns eligible according to the study criteria. Of these, 1033 underwent a newborn screening test, and serum TFT at least 2 weeks after birth. Eight babies with congenital hypothyroidism were detected independently by both the newborn screening program and at the TFT performed at 2 weeks of age.Conclusions: No added clinical benefit was found in retesting newborns of hypothyroid mothers for thyroid function in addition to the newborn screening program. What is Known • Performing thyroid function test 2 weeks after birth is a common practice in newborn to a mother with hypothyroidism. • Neonatal screening program for thyroid function is also done in these newborns. What is New • No newborn was found to have a normal newborn screening test but abnormal serum thyroid function test. • No added clinical benefit was found in retesting newborns of hypothyroid mothers for thyroid function in addition to the newborn screening program.

The natural history of congenital hypothyroidism with delayed TSH elevation in neonatal intensive care newborns.

OBJECTIVE: To assess the clinical and neurological outcomes in newborns with primary congenital hypothyroidism presented with delayed TSH elevation (dTSH), and to define parameters that may predict the evolution of transient vs. permanent hypothyroidism in these newborns. DESIGN AND PATIENTS: An observational study was performed of a cohort of 113 children with a history of dTSH. MEASUREMENTS: Birth parameters, thyroid screening results, thyroid gland imaging, levothyroxine dose and neurological outcome were compared between newborns with spontaneous recovery and children with a final diagnosis of either transient or permanent hypothyroidism. RESULTS: Of the children with a history of dTSH, 93% demonstrated recovery, either spontaneously or following levothyroxine treatment (transient hypothyroidism). Newborns with spontaneous recovery demonstrated milder thyroid dysfunction at the newborn screening compared to those who started levothyroxine treatment. Levothyroxine dose was lower in children with transient vs. permanent hypothyroidism only during the first 6 months of life; otherwise, these groups were similar in birth parameters, thyroid screening results and gland images. Seventeen out of 61 children (28%) that underwent neurological assessment demonstrated a developmental delay. Duration of treatment was highly variable in children with transient hypothyroidism. CONCLUSIONS: Thyroid dysfunction is transient in most cases of dTSH. No reliable parameters can predict a priori transient vs. permanent hypothyroidism.

Characteristics of Delayed Thyroid Stimulating Hormone Elevation in Neonatal Intensive Care Unit Newborns.

OBJECTIVES: To elucidate the incidence, clinical characteristics, and short-term outcome of delayed thyroid stimulating hormone (TSH) elevation (dTSH) in a large cohort of newborns admitted to the neonatal intensive care unit. STUDY DESIGN: Data were gathered from a cohort of 13 201 newborns admitted to the neonatal intensive care unit born between January 1, 2008, and October 31, 2014, who underwent TSH measurements because of low T4 levels on the second screen. The data from the newborn screening program included gestational age, birth weight (BW), T4 levels, and short-term outcome. RESULTS: Of 13 201 newborns, 333 (1:40) presented with dTSH (TSH >15 IU/L). dTSH had a peak proportion at gestational age of 37-39 weeks, and 66% of the patients had BW >1500 g. T4 levels in the 333 patients were negatively correlated with TSH levels (R = -0.505; P < .001), and significantly lower than levels in the other newborns: 5.9 ± 2.8 vs 7.6 ± 1.7 µg/dL; P < .001. TSH levels in dTSH newborns were already higher on the initial screen compared with the other newborns: 8.3 ± 5.2 vs 4.2 ± 3.7 IU/L; P < .001. Fifty-eight percent of 193 patients with dTSH were started on levothyroxine treatment. CONCLUSIONS: dTSH has a higher incidence than previously reported, especially among newborns with BW >1500 g. Relatively high TSH and low T4 levels on the initial and second screen respectively are predictors for dTSH. Levothyroxine treatment is required in most cases.

Hypothyroxinemia and Risk for Transient Tachypnea of Newborn.

Transient tachypnea of newborn is associated with hypothyroxinemia in animals via decreased stimulation of beta-adrenergic receptors and Na-K-ATPase activity. In 26 549 term neonates, serum total thyroxine <14 ug/dL, male sex, and elective cesarean delivery were significantly associated with greater risk for transient tachypnea of newborn.

Primary and maternal 3-methylcrotonyl-CoA carboxylase deficiency: insights from the Israel newborn screening program.

BACKGROUND: 3-Methylcrotonyl-CoA carboxylase deficiency (3MCCD) is an inborn error of leucine catabolism. Tandem mass spectrometry newborn screening (NBS) programs worldwide confirmed 3MCCD to be the most common organic aciduria and a relatively benign disorder with favorable outcome. In addition, several asymptomatic 3MCCD mothers were initially identified following abnormal screening of their healthy babies and were appropriately termed maternal 3MCCD. METHODS: This is a retrospective study that summarizes all the clinical, biochemical, and genetic data collected by questionnaires of all 3MCCD individuals that were identified by the extended Israeli NBS program since its introduction in 2009 including maternal 3MCCD cases. RESULTS: A total of 36 3MCCD subjects were diagnosed within the 50-month study period; 16 were classified primary and 20 maternal cases. Four additional 3MCCD individuals were identified following sibling screening. All maternal 3MCCD cases were asymptomatic except for one mother who manifested childhood hypotonia. Most of the primary 3MCCD individuals were asymptomatic except for two whose condition was also complicated by severe prematurity. Initial dried blood spot (DBS) free carnitine was significantly lower in neonates born to 3MCCD mothers compared with newborns with primary 3MCCD (p = 0.0009). Most of the mutations identified in the MCCC1 and MCCC2 genes were missense, five of them were novel. CONCLUSIONS: Maternal 3MCCD is more common than previously thought and its presence may be initially indicated by low DBS free carnitine levels. Our findings provide additional confirmation of the benign nature of 3MCCD and we suggest to exclude this disorder from NBS programs.

Outcomes in Maternal Graves' Disease: A Population-Based Mother-Infant Dyad Cohort Study.

Background: Graves' disease has been associated with adverse pregnancy, labor and delivery, and neonatal outcomes. Thyroid function levels, assessed during newborn screening (NBS), can serve as indicators of the adaptation in the hypothalamic-pituitary-thyroid axis. We utilized data from the national thyroid NBS program to investigate the characteristics of the mother-infant dyad of term infants born to mothers with past or active Graves' disease. Methods: The dataset of the Israeli NBS for thyroid function was linked with the electronic records of a tertiary medical center to generate a unified database of mothers and their term infants born between 2011 and 2021. The MDClone big data platform extracted maternal, pregnancy, disease course, labor and delivery, and neonatal characteristics of the mother-infant dyads. Results: Out of 103,899 registered mother-infant dyads, 292 (0.3%) mothers had past or active Graves' disease. A forward multivariate linear regression demonstrated that Graves' disease did not significantly affect NBS total thyroxine (tT4) levels (p = 0.252). NBS tT4 levels in infants born to mothers with active Graves' disease were higher than those observed in the general Israeli population (p < 0.001). Mothers with Graves' disease more frequently used assisted reproductive technology (12.7% vs. 9.0%, respectively, p = 0.012; odds ratio [OR] = 1.46 [CI 1.03-2.07], p = 0.031), and had more gestational hypertension (3.9% vs. 1.1%, p < 0.001; OR = 3.53 [CI 1.92-6.47], p < 0.001), proteinuria (2.5% vs. 0.9%, p < 0.001; OR = 3.03 [CI 1.43-6.45], p = 0.004), cesarean sections (26.4% vs. 19.7%, p = 0.029; OR = 1.46 [CI 1.13-1.90], p = 0.004), prelabor rupture of membranes (15.4% vs. 4.1%, p < 0.001; OR = 4.3 [CI 3.13-5.91], p < 0.001), and placental abnormalities (5.1% vs. 2.0%, p < 0.001; OR = 2.64 [CI 1.57-4.44]; p < 0.001). Their infants had lower adjusted birthweight z-scores (-0.18 ± 0.94 vs. -0.03 ± 0.90, p = 0.007) and were more likely to be small for gestational age (12.0% vs. 8.1%, p = 0.005; OR = 1.54 [CI 1.08-2.19], p = 0.018). Conclusions: Neonatal thyroid function levels were affected by maternal Graves' disease only when the disease was active during gestation. Moreover, maternal Graves' disease was also associated with an increased risk of adverse outcomes for the mother-infant dyad.

The Natural Course of Newborns with Transient Congenital Hypothyroidism.

OBJECTIVES: The incidence of congenital hypothyroidism (CH) has increased worldwide over the last decades mainly due to the lowering of screening thresholds, resulting in an increased identification of newborns with transient CH. Several studies reported the prevalence and the predictive parameters of transient CH but reports on the long-term outcome are rare. This study aimed to assess the long-term course of neonates with transient CH. DESIGN: Neonates diagnosed with transient and permanent CH between the years 1998 to 2018 at the Pediatric Endocrine Institute of Ha'Emek Medical Center were enrolled in the study. Data were retrieved retrospectively from medical files. RESULTS: Included in the study were 76 newborns (45M,59%) with transient CH and 53 (25M,47%) with permanent CH. The major cause of transient CH was prematurity (29%) and subclinical hypothyroidism (30%). During retrospective follow-ups of up to 23 years, reinitiation of LT4 therapy was not required apart from four patients with underlying syndromic etiologies. Neurodevelopmental impairment occurred in 16% of children with transient CH compared with 29.4% in the permanent CH group. CONCLUSIONS: Transient CH is frequent among preterm infants but is limited to infancy. SCH frequently presents as overt hypothyroidism at birth but in most cases the requirement for LT4 supplemental therapy is limited to the first years of life, suggesting that long-term follow-up of thyroid function tests may be unnecessary for non-syndromic children. The high rate of neurodevelopmental impairment in newborns with transient CH emphasizes the need for neurodevelopmental monitoring in these patients.

Clinical and Molecular Characteristics and Long-term Follow-up of Children With Pseudohypoparathyroidism Type IA.

CONTEXT: Pseudohypoparathyroidism type IA (PHPIA) is a rare genetic disorder characterized by hormone resistance and a typical phenotype named Albright hereditary osteodystrophy. Unawareness of this rare disease leads to delays in diagnosis. OBJECTIVE: The aims of this study were to describe the clinical and molecular characteristics of patients with genetically confirmed GNAS mutations and to evaluate their long-term outcomes. METHODS: A retrospective search for all patients diagnosed with PHPIA in 2 referral centers in Israel was conducted. RESULTS: Nine children (8 females) belonging to 6 families were included in the study. Five patients had GNAS missense mutations, 2 had deletions, and 2 had frameshift mutations. Four mutations were novel. Patients were referred at a mean age of 2.4 years due to congenital hypothyroidism (5 patients), short stature (2 patients), or obesity (2 patients), with a follow-up duration of up to 20 years. Early obesity was observed in the majority of patients. Elevated parathyroid hormone was documented at a mean age of 3 years; however, hypocalcemia became evident at a mean age of 5.9 years, about 3 years later. All subjects were diagnosed with mild to moderate mental retardation. Female adult height was very short (mean -2.5 SD) and 5 females had primary or secondary amenorrhea. CONCLUSION: Long-term follow-up of newborns with a combination of congenital hypothyroidism, early-onset obesity, and minor dysmorphic features associated with PHPIA is warranted and molecular analysis is recommended since the complete clinical phenotype may develop a long time after initial presentation.

Insights into Central Congenital Hypothyroidism: A Multicenter Retrospective Analysis.

CONTEXT: Central congenital hypothyroidism (CCH) is a thyroid hormone deficiency at birth caused by inadequate pituitary stimulation of the thyroid gland. Although primary CH has been studied extensively, studies on CCH are sparse. OBJECTIVES: To assess the prevalence of CCH in Israel and describe its clinical features, neonatal screening results, and outcomes. DESIGN: Multicenter cross-sectional retrospective chart review. SETTING: Nine pediatric endocrine units throughout Israel. PATIENTS: Patients diagnosed with CCH in 1987-2021 were categorized into early (within 14 days of life) and late (after 14 days) diagnosis groups. Newborn screening (NBS) results were retrospectively retrieved from the national NBS program dataset. RESULTS: CCH prevalence in Israel was about 1:42,800 live births. Subjects were 94 patients (54 males), of these, 84% had multiple pituitary hormone deficiencies and 16% had isolated CCH. The median age at diagnosis was 50 days (range, 1-8760), with 66% having moderate to severe hypothyroidism. NBS detected only three infants. Early diagnosis occurred in 34% due to hypopituitarism, while 66% were diagnosed later due to growth and developmental delays. Neurodevelopmental sequelae included mental retardation (12%), learning difficulties (18%), delayed speech (27%), and motor clumsiness (19%), with no significant differences in outcomes between early and late diagnosis. CONCLUSIONS: Despite high rates of neurodevelopmental sequelae, no differences were found between early and late diagnosis groups. Further research is needed to assess the impact of delayed diagnosis on neurological outcomes in newborns with CCH. Improved strategies for detecting CHH in newborns are also necessary.

Newborn screening for severe T and B cell immunodeficiency in Israel: a pilot study.

BACKGROUND: Enumeration of T cell receptor excision circles (TREC) was recently adopted as a neonatal screening assay for severe combined immunodeficiency (SCID). Enumeration of kappa-deleting recombination excision circle (KREC) copy numbers can be similarly used for early assessment of B cell lymphopenia. OBJECTIVE: To assess the ability of TREC and KREC counts to identify patients with combined T and B cell immunodeficiency in a pilot study in Israel. METHODS: We studied seven children born in Israel during the years 2010-2011 and later diagnosed with SCID, and an additional patient with pure B cell immunodeficiency. TREC and KREC in peripheral blood upon diagnosis and in their neonatal Guthrie cards were analyzed using real-time quantitative polymerase chain reaction, as were Guthrie cards with dried blood spots from healthy newborns and from normal and SCID-like controls. RESULTS: The first features suggestive of SCID presented at age 3.1 +/- 2.4 months in all patients. Yet, the diagnosis was made 4.1 +/- 2.9 months later. Their TREC were undetectable or significantly low at their clinical diagnosis and in their originally stored Guthrie cards, irrespective of the amount of their circulating T cells. KREC were undetectable in six SCID patients who displayed B cell lymphopenia in addition to T cell lymphopenia. KREC were also undetectable in one patient with pure B cell immunodeficiency. CONCLUSIONS: TREC and KREC quantification are useful screening tests for severe T and B cell immunodeficiency. Implementation of these tests is highly important especially in countries such as Israel where a high frequency of consanguinity is known to exist.

Hereditary orotic aciduria identified by newborn screening.

Introduction: Hereditary orotic aciduria is an extremely rare, autosomal recessive disease caused by deficiency of uridine monophosphate synthase. Untreated, affected individuals may develop refractory megaloblastic anemia, neurodevelopmental disabilities, and crystalluria. Newborn screening has the potential to identify and enable treatment of affected individuals before they become significantly ill. Methods: Measuring orotic acid as part of expanded newborn screening using flow injection analysis tandem mass spectrometry. Results: Since the addition of orotic acid measurement to the Israeli routine newborn screening program, 1,492,439 neonates have been screened. The screen has identified ten Muslim Arab newborns that remain asymptomatic so far, with DBS orotic acid elevated up to 10 times the upper reference limit. Urine organic acid testing confirmed the presence of orotic aciduria along with homozygous variations in the UMPS gene. Conclusion: Newborn screening measuring of orotic acid, now integrated into the routine tandem mass spectrometry panel, is capable of identifying neonates with hereditary orotic aciduria.

Usefulness of thyroid function assessment in infants born to mothers with thyroid dysfunction during pregnancy.

Introduction: Maternal thyroid disease is considered as a risk factor for abnormal thyroid function at birth, as well as for long-term morbidity in offspring. The potential harmful effects on the neonate had led to the clinical practice of thyroid function assessment in infants born to mothers with thyroid disease during pregnancy. In this study, we evaluated the usefulness of routine thyroid function tests for every newborn of a mother with thyroid dysfunction. Methods: Data were collected retrospectively from the medical files of mothers diagnosed with thyroid disease and their infants (496 mother-neonate pairs). All mothers with diagnosed thyroid disease who gave birth in the years 2016-2019 at our medical center were included. Results: Hypothyroidism was the most common maternal diagnosis (91.4%), among which 48.7% had Hashimoto's thyroiditis. Hyperthyroidism was diagnosed in 8.6% of the cohort - 71.6% of them with Graves' disease. None of the newborns was diagnosed with congenital hypothyroidism in the screening program. Thyroid-stimulating hormone was >10 mIU/L in 14.6% and >20 mUI/L in 2.2%; all had free thyroxine within normal range. Serum thyroid function test identified four infants with thyroid disease; two had congenital hypothyroidism not related to maternal thyroid disease, one had transient familial congenital hypothyroidism and one had neonatal Graves' disease. Conclusions: Thyroid function testing for all newborns of mothers with thyroid dysfunction seems redundant. However, in cases of congenital hypothyroidism in siblings, thyroid function test, in addition to newborn thyroid screening, is recommended, and more careful follow-up is indicated. In maternal Graves' disease, thyroid function test on days 2-3 of life is recommended.