Newborn Screening Results Research Articles

Preferences of parents from diverse backgrounds on genomic screening of apparently healthy newborns.

Genomic sequencing has been proposed as a strategy to expand newborn screening. Perspectives on genomic newborn screening from parents of diverse racial, ethnic, and socioeconomic backgrounds are needed to shape equitable implementation of this modality. We conducted 20 semi-structured interviews (15 English, 5 Spanish) and seven focus groups (4 English, 3 Spanish) with parents from diverse backgrounds to assess their perspectives regarding which disorders and variants might be screened, data privacy, and barriers to pursuing specialized care. Parents felt that genomic newborn screening would provide them with improved understanding of their children's health and had the potential to yield health and personal benefits. Themes that became evident included: interest in childhood and family health risks, the value of emotional preparation and personal planning, understanding of uncertain and low-risk results, concerns regarding data privacy, and concerns about support following the receipt of a positive newborn screening result. The expected benefits and concerns expressed by parents of diverse backgrounds regarding genomic newborn screening should guide future policy decisions. Their preferences should be considered prior to the implementation of large-scale genomic newborn screening programs.

Newborn Genomic Sequencing Needs Confirmation but Not Repeating

Newborn screening (NBS) has been one of the big innovations in public health. It has grown over the decades, especially with the introduction of tandem mass spectrometry. However, it is likely to expand significantly in the coming decades with the introduction of genomic testing. Traditionally, in NBS, there has been a pattern of repeat testing for confirmation and follow-up diagnostic testing. This follow-up is critical as NBS is a screening program. This pathway is appropriate for low-cost tests, but if public health authorities are going to invest in high-cost screening such as whole-genome sequencing, they are likely to baulk at repeating these expensive tests in a diagnostic setting. Our study investigates whether screening-grade data from NBS can be transitioned into diagnostic-grade data using a panel of single-nucleotide variants (SNVs) on a diagnostic specimen. These SNVs could be used to link the diagnostic specimen with all of the provenance requirements associated with routine pathology and the NBS genomic data. This strategy has large cost benefits and opens up the rapid use of NBS genomic data should a child present in an acute care setting and a genetic diagnosis is suspected. This approach will greatly speed up the confirmation of positive NBS results and reduce family anxiety due to delayed diagnostic testing.

The Value of Reducing Inconclusive and False-Positive Newborn Screening Results for Congenital Hypothyroidism, Congenital Adrenal Hyperplasia and Maple Syrup Urine Disease in The Netherlands.

Inconclusive and false-positive newborn screening (NBS) results can cause parental stress and increase healthcare expenditures. These results can be reduced by improving NBS algorithms. This was recently done for Congenital Hypothyroidism (CH), Congenital Adrenal Hyperplasia (CAH) and Maple Syrup Urine Disease (MSUD) in the Dutch NBS program. The current study estimates the financial consequences of these improved algorithms related to the reduction in inconclusive results and false-positives. For each improved algorithm, the care pathway of an inconclusive/false-positive result was analyzed. The costs associated with the improvements, based on the change in inconclusive results/false-positives, were assessed to estimate the cost reduction per year. The improvements resulted in a reduction of inconclusive results and/or false-positives, without increasing false-negatives. For CH, false positives decreased by 26 per year with a related cost reduction of EUR 31,156. For CAH, 95 second heel punctures and seven false-positives per year were avoided, leading to a related cost reduction of EUR 7340. For MSUD, five false-positives per year were avoided with a related cost reduction of EUR 11,336. The improved screening algorithms led to a cost reduction of EUR 49,832 annually. Together with the known negative psychosocial effects associated with an inconclusive or false-positive NBS result, these results highlight the importance of improving NBS algorithms.

Gestational diabetes mellitus and the hearing of newborns:A nested case-control study in tropical province of China

ObjectiveThis study aims to determine the association of gestational diabetes mellitus (GDM) and the results of newborn hearing screening(NHS). MethodsA nested case-control study was conducted in a cohort of newborns who were born between June 2021 to December 2021 and underwent neonatal hearing screening.GDM was diagnosed according to the 75 g 2 h oral glucose tolerance test (OGTT) at 24–28 gestational weeks.A total of 369 pregnant women at the same hospital were individually matched in a 1:2 ratio by maternal age (±2 years), gestational age (±3 days) and sex of newborn.Chi-square test was utilized to evaluate associations between GDM and the results of NHS. ResultsAbnormal NHS results in the GDM group was more frequent than non-GDM group.When comparing the two groups (GDM case and contol), we found significant differences (p < 0.05) between them.Whereas the difference was not statistically significant (p > 0.05) by delivery modes in both case and control groups. ConclusionMaternal history of GDM could lead to significantly higher failling rate of NHS.

One-Year Pilot Study Results of Newborn Screening for Spinal Muscular Atrophy in the Republic of Croatia.

Spinal muscular atrophy (SMA) is a neuromuscular and neurodegenerative disease caused by the homozygous deletion of SMN1 exon 7 in 95% of cases. The prognosis for SMA patients has improved with the development of disease-modifying therapies, all of which are available in Croatia. The best treatment outcomes occur when therapy is applied before symptoms appear, making newborn screening (NBS) for SMA a crucial factor. Since SMA NBS is the first genetic test performed in our laboratory, for successful implementation of the program, we had to overcome logistical and organizational issues. Herein, we present the results of the SMA NBS during the one-year pilot project in Croatia and verify the suitability of the Targeted qPCR™ SMA assay for SMA NBS. The pilot project started on 1 March 2023 in the Department for Laboratory Diagnostics of the University Hospital Center Zagreb. A total of 32,655 newborns were tested. Five SMA patients were detected, and their diagnoses were confirmed by the multiplex ligation-dependent probe amplification (MLPA) assay. There have been no false positive or false negative results, to our knowledge so far. The incidence of SMA determined during the pilot study is consistent with the SMA incidence data from other European countries.

Insights into Central Congenital Hypothyroidism: A Multicenter Retrospective Analysis.

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. To assess the prevalence of CCH in Israel and describe its clinical features, neonatal screening results, and outcomes. Multicenter cross-sectional retrospective chart review. Nine pediatric endocrine units throughout Israel. 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. 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. 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.

Improved detection of cystic fibrosis by the California Newborn Screening Program for all races and ethnicities.

Newborn screening (NBS) for cystic fibrosis (CF) is universal in the United States. Protocols vary but include an immunoreactive trypsinogen (IRT) level and CFTR variant panel. California CF NBS has a 3-step screening: IRT level, variant panel, and CFTR sequencing if only one variant identified on panel. This was a cohort study of infants with CF born in California (2007-2021) to examine racial and ethnic differences in having a false-negative NBS result for CF and at which step the false-negative occurred. We examined how different CFTR variant panels would improve detection of variants by race and ethnicity: original 39-variant panel, current 75-variant panel, and all 402 disease-causing CFTR variants in the CFTR2 database. Of the 912 infants born in California with CF, 84 had a false-negative result: 38 due to low IRT level and 46 with a high IRT value (but incomplete variant detection). Asian (OR 6.3) and Black infants (OR 2.5) were more likely to have a false-negative screening result than non-Hispanic white infants. The majority of false-negative screening (but CF diagnosis) cases among American Indian/Native Alaskan and non-Hispanic White infants were due to low IRT levels. The majority of Asian and Hispanic infants with false-negative screening had no variants detected. Detection of two CFTR variants was improved with the 75-variant panel in Black, Hispanic, and non-Hispanic White infants and with the 402-variant panel in Black, Hispanic, non-Hispanic White, and other race infants. Larger CFTR panels in NBS improved the detection of CF in all races and ethnicities.

Severe adrenal insufficiency in six neonates with normal newborn screening for CAH.

Newborn screening (NBS) reduces the risk of mortality in congenital adrenal hyperplasia (CAH), mainly due to the salt-wasting form of 21-hydroxylase deficiency. There is limited knowledge regarding the results of NBS in non-CAH primary adrenal insufficiency (non-CAH PAI). Clinical and NBS for CAH data of neonates who were diagnosed with non-CAH PAI between January and December 2022 were examined. Patients (n = 6, 4 females) were presented with severe hyperpigmentation (n = 6), hypoglycemia (n = 4), hyponatremia (n = 3), hyperkalemia (n = 1), respiratory distress syndrome (n = 1) between 3rd hour to 2 months of life. All had normal NBS results. The median first-tier 17-hydroxyprogesterone (17OHP) concentration in NBS for CAH was 0.14 ng/mL (range; 0.05-0.85). Molecular studies revealed biallelic mutations in the MC2R (n = 4; 3 homozygous, 1 compound heterozygous), MRAP (n = 1) and STAR (n = 1) genes. Glucocorticoid with or without mineralocorticoid replacement was initiated once the diagnosis ofnon-CAH PAI was established. Neonates with non-CAH PAI have always normal NBS due to persistently low 17OHP, even when these newborn infants are severely symptomatic for adrenal insufficiency. Clinicians should be alert for signs of adrenal insufficiency in neonates, even if the patient has a 'normal' screening for CAH, so as not to delay diagnosis and treatment. This fact should be kept in mind particularly in countries where these conditions are more common than elsewhere.

Geographic, Sociodemographic, and Clinical Factors Associated With Parental Self-Efficacy in Pediatric Patients With Hearing Loss.

To identify geographic, sociodemographic, and clinical factors associated with parental self-efficacy in a diverse cohort of deaf or hard-of-hearing (DHH) children. Cross-sectional study. Tertiary children's hospital. Four hundred forty parents of DHH children aged 0 to 17 completed the 25-item Scale of Parental Involvement and Self-Efficacy (SPISE) survey from 2014 to 2022. Residential addresses were geocoded and assigned Area Deprivation Index and Social Vulnerability Index rankings, and univariable and multivariable analyses were conducted using sociodemographic and clinical variables, including sex, race/ethnicity, insurance type, survey language, age at the survey, comorbidities, newborn hearing screening results, and hearing loss laterality and severity. Compared to English and Spanish-speaking parents, Chinese-speaking parents were associated with overall lower parental self-efficacy and involvement (regression coefficient = -0.518, [-0.929, -0.106]), Cohen's d = 0.606) and lower scores on items related to their ability to affect multiple aspects of their child's development and expression of thoughts as well as competency in checking and putting on their child's sensory device. Across univariable and multivariable analyses, besides Chinese language, all other sociodemographic, clinical, and geographic variables were not associated with SPISE score. To achieve the best patient outcomes, care teams can use the SPISE to evaluate parental self-efficacy and provide targeted support to parents at risk for having lower knowledge and confidence scores about critical skills necessary to facilitate their child's auditory access and language development. Notably, this study found similar reports of parental efficacy across various sociodemographic, clinical, and geographic variables but significantly lower SPISE scores in Chinese-speaking families.

Newborn Screening for Severe T and B Cell Lymphopenia Using TREC/KREC Detection: A Large-Scale Pilot Study of 202,908 Newborns.

Newborn screening (NBS) for severe inborn errors of immunity (IEI), affecting T lymphocytes, and implementing measurements of T cell receptor excision circles (TREC) has been shown to be effective in early diagnosis and improved prognosis of patients with these genetic disorders. Few studies conducted on smaller groups of newborns report results of NBS that also include measurement of kappa-deleting recombination excision circles (KREC) for IEI affecting B lymphocytes. A pilot NBS study utilizing TREC/KREC detection was conducted on 202,908 infants born in 8 regions of Russia over a 14-month period. One hundred thirty-four newborns (0.66‰) were NBS positive after the first test and subsequent retest, 41% of whom were born preterm. After lymphocyte subsets were assessed via flow cytometry, samples of 18 infants (0.09‰) were sent for whole exome sequencing. Confirmed genetic defects were consistent with autosomal recessive agammaglobulinemia in 1/18, severe combined immunodeficiency - in 7/18, 22q11.2DS syndrome - in 4/18, combined immunodeficiency - in 1/18 and trisomy 21 syndrome - in 1/18. Two patients in whom no genetic defect was found met criteria of (severe) combined immunodeficiency with syndromic features. Three patients appeared to have transient lymphopenia. Our findings demonstrate the value of implementing combined TREC/KREC NBS screening and inform the development of policies and guidelines for its integration into routine newborn screening programs.

Screening T4 and TSH in Early Detection of Congenital Hypothyroidism in Newborns: What’s the Dilemma?

Untreated congenital hypothyroidism (CH) leads to intellectual disability. Newborn screening (NBS) for CH should be done on all infants. Prompt diagnosis by NBS leads to early and adequate treatment outcomes in very normal neurocognitive outcomes in adulthood. Newborn screening (NBS) for congenital hypothyroidism (CH) is one of the major achievements in preventive medicine. Most neonates born with CH have a normal appearance and no detectable physical signs. Blood spot thyroid stimulating hormone (TSH), thyroxine (T4), or both can be used for CH screening. The latter is more sensitive but not cost-effective, so screening by TSH or T4 is used in various programs worldwide. TSH screening is more specific in the diagnosis of CH. T4 screening is more sensitive in detecting newborns with rare hypothalamic-pituitary-hypothyroidism, but it’s less specific with a high frequency of false positives especially in low birth weight and premature infants. NBS alone is not sufficient to prevent adverse outcomes from CH in a pediatric population. In addition to NBS, the management of CH requires timely confirmation of the diagnosis and accurate interpretation of thyroid function testing, effective treatment, and consistent follow-up. Doctors need to consider hypothyroidism in the face of clinical symptoms, even if NBS thyroid test results are normal. When clinical symptoms and signs of hypothyroidism appear (such as large posterior fontanelles, large tongue, umbilical hernia, prolonged jaundice, constipation, lethargy, and/or hypothermia), measurement of serum thyroid hormone and free thyroxine is indicated, regardless of NBS results. So all these babies should be treated as having CH during the first 3 years of life, taking into account the risk of mental retardation. Re-evaluation after 3 years is required in such patients.

Newborn Hearing Screening Results for Infants With Prenatal Opioid Exposure in Southern Appalachia.

Infants prenatally exposed to opioids exhibit withdrawal symptomology that introduce physiological noise and can impact newborn hearing screening results. This study compared the referral rate and physiological noise interpreted by number of trials rejected due to artifact on initial newborn hearing screenings of infants with prenatal opioid exposure (POE) and infants with no opioid exposure (NOE). Furthermore, within the POE group, it examined the relationship of referral rates with severity of withdrawal symptomology, and with maternal and infant risk factors. This study used a retrospective cohort design of electronic medical records from six delivery hospitals in South-Central Appalachia. Newborn hearing screenings were conducted using automated auditory brainstem response (ABR) for 334 infants with POE and 226 infants with NOE. Severity of withdrawal symptomology was measured using the Modified Finnegan Neonatal Abstinence Scoring Tool, which includes observation of behaviors that introduce physiological noise. There was no significant difference in newborn hearing screening referral rate between infants with POE and infants with NOE. Referral rate was not affected by maternal or infant risk factors. Infants with POE had statistically significant higher artifact (defined as rejected ABR sweeps) than infants with NOE. There was a strong positive correlation between Finnegan scores and artifact but not referral rates. Sensitivity and specificity analysis indicated artifact decreased substantially after Day 4 of life. Referral rates of infants with POE were similar to those of infants with NOE. Nevertheless, the withdrawal symptomology of infants with POE introduces physiological noise reflected as artifact on ABR, which can affect efficiency of newborn hearing screenings.

Retrospective Review of Positive Newborn Screening Results for Isovaleric Acidemia and Development of a Strategy to Improve the Efficacy of Newborn Screening in the UK.

Since the UK commenced newborn screening for isovaleric acidemia in 2015, changes in prescribing have increased the incidence of false positive (FP) results due to pivaloylcarnitine. A review of screening results between 2015 and 2022 identified 24 true positive (TP) and 84 FP cases, with pivalate interference confirmed in 76/84. Initial C5 carnitine (C5C) did not discriminate between FP and TP with median (range) C5C of 2.9 (2.0-9.6) and 4.0 (1.8->70) µmol/L, respectively, and neither did Precision Newborn Screening via Collaborative Laboratory Integrated Reports (CLIR), which identified only 1/47 FP cases. However, among the TP cases, disease severity showed a correlation with initial C5C in 'asymptomatic' individuals (n = 17), demonstrating a median (range) C5C of 3.0 (1.8-7.1) whilst 'clinically affected' patients (n = 7), showed a median (range) C5C of 13.9 (7.7-70) µmol/L. These findings allowed the introduction of dual cut-off values into the screening algorithm to reduce the incidence of FPs, with initial C5C results ≥ 5 µmol/L triggering urgent referral, and those >2.0 and <5.0 µmol/L prompting second-tier C5-isobar testing. This will avoid delayed referral in babies at particular risk whilst reducing the FP rate for the remainder.

Expanded Newborn Screening for Inborn Errors of Metabolism in Hong Kong: Results and Outcome of a 7 Year Journey.

Newborn screening (NBS) is an important public health program that aims to identify pre-symptomatic healthy babies that will develop significant disease if left undiagnosed and untreated. The number of conditions being screened globally is expanding rapidly in parallel with advances in technology, diagnosis, and treatment availability for these conditions. In Hong Kong, NBS for inborn errors of metabolism (NBSIEM) began as a pilot program in October 2015 and was implemented to all birthing hospitals within the public healthcare system in phases, with completion in October 2020. The number of conditions screened for increased from 21 to 24 in April 2016 and then to 26 in October 2019. The overall recruitment rate of the NBS program was 99.5%. In the period between October 2015 and December 2022, 125,688 newborns were screened and 295 were referred back for abnormal results. The recall rate was reduced from 0.26% to 0.12% after the implementation of second-tier testing. An inherited metabolic disorder (IMD) was eventually confirmed in 47 infants, making the prevalence of IMD in Hong Kong 1 in 2674. At the time of the NBS result, 78.7% of the newborns with IMD were asymptomatic. There were two deaths reported: one newborn with methylmalonic acidemia cobalamin B type (MMACblB) died after the initial crisis and another case of carnitine palmitoyltransferase II deficiency (CPTII) died at 18 months of age after metabolic decompensation. The most common IMD noted were disorders of fatty acid oxidation metabolism (40%, 19 cases), closely followed by disorders of amino acid metabolism (38%, 18 cases), with carnitine uptake defect (19.1%, 9 cases) and citrullinemia type II (17%, 8 cases) being the two most common IMD picked up by the NBSIEM in Hong Kong. Out of the all the IMDs identified, 19.1% belonged to diverse ethnic groups. False negative cases were reported for citrullinemia type II and congenital adrenal hyperplasia during this period.

Parental Engagement in Identifying Information Needs After Newborn Screening for Families of Infants with Suspected Athymia

Congenital athymia is a rare T-lymphocytopaenic condition, which requires early corrective treatment with thymus transplantation (TT). Athymic patients are increasingly identified through newborn screening (NBS) for severe combined immunodeficiency (SCID). Lack of relatable information resources contributes to challenging patient and family journeys during the diagnostic period following abnormal NBS results. Patient and Public Involvement and Engagement (PPIE) activities, including parental involvement in paediatrics, are valuable initiatives to improve clinical communication and parental information strategies. Parents of infants with suspected athymia were therefore invited to discuss the information they received during the diagnostic period following NBS with the aim to identify parental information needs and targeted strategies to address these adequately. Parents reported that athymia was not considered with them as a possible differential diagnosis until weeks after initial NBS results. Whilst appropriate clinical information about athymia and TT was available upon referral to specialist immunology services, improved access to easy-to-understand information from reliable sources, including from clinical nurse specialists and peer support systems, remained desirable. A roadmap concept, with written or digital information, addressing parental needs in real time during a potentially complex diagnostic journey, was proposed and is transferrable to other inborn errors of immunity (IEI) and rare diseases. This PPIE activity provides insight into the information needs of parents of infants with suspected athymia who are identified through SCID NBS, and highlights the role for PPIE in promoting patient- and family-centred strategies to improve IEI care.

Inherited Pediatric Neurotransmitter Disorders: Case Studies and Long-Term Outcomes

AbstractPrimary pediatric neurotransmitter disorders include genetic defects of neurotransmitter metabolism that may mimic common neurological conditions in children. Our objective was to evaluate the clinical experience and outcomes of affected patients. Five patients with primary neurotransmitter defects were identified in the neurometabolic database between 2004 and 2022. Two patients with 6-pyruvoyltetrahydropterin synthase deficiency and one with pyridoxine-dependent epilepsy (PDE) presented in the neonatal period. One patient with succinic semialdehyde dehydrogenase (SSADH) deficiency and one with aromatic l-amino acid decarboxylase (AADC) deficiency presented in later life. A diagnosis of cerebral palsy was revised following biochemical confirmation of SSADH deficiency. AADC deficiency was confirmed via exome sequencing and reduced activity on enzyme assay. Late diagnosis in the latter two cases was likely due to a low index of suspicion and lack of access to diagnostic tests in the country of origin. In two children with tetrahydrobiopterin deficiency, newborn screening results and atypical clinical features prompted investigations. An early diagnosis of PDE was established based on presenting features, a high index of suspicion, the presence of an identifiable biochemical marker and molecular genetic testing. Pediatric neurotransmitter disorders can be diagnosed based on a high clinical index of suspicion, availability of biochemical markers, and molecular genetic testing. These disorders, though rare, need to be included in the differential diagnosis of common neurological presentations in children as they may be potentially treatable. Outcomes and influencing factors in the present series are discussed in comparison to published data.

Genetic counselors’ perspectives on genomic screening of apparently healthy newborns in the United States

PurposeThere is growing international interest in using genomic sequencing to screen newborns and children for treatable genomic conditions. Although recent research has demonstrated increasing support for using genomic sequencing to screen newborns and children for treatable genomic conditions among various stakeholders, little is known about the perspectives of genetic counselors (GCs) in the United States, who are frequently engaged in the disclosure of positive newborn screening results and coordination of follow-up testing and management. MethodsThis study utilized a cross-sectional 3-section survey to explore GCs’ perspectives on the benefits, limitations, and ethical and practical considerations of genomic sequencing in newborns as an adjunct screen to standard newborn screening (NBS). Additionally, we evaluated GCs’ views on specific genes that could be added to NBS via sequencing. ResultsOf 176 GCs who participated in the study, most endorsed the addition of NBSeq for conditions that typically manifest in childhood and have a well-defined treatment or management protocol. Some perspectives, such as attitudes toward health inequity, varied by practice region. Most respondents endorsed 13 of 25 specific genetic conditions for inclusion in NBSeq. ConclusionOur findings demonstrate GCs’ support for the expansion of NBS using genomic sequencing in the United States and the need for ongoing investigation of ethical and practical concerns related to its implementation.

Selective Screening for Inborn Errors of Metabolism Using Tandem Mass Spectrometry in Newborns of the West Kazakhstan: Pilot Study

Tandem mass spectrometry can detect and quantify many metabolites in a single blood spot to diagnose amino acid disorders, organic acids, fatty acid oxidation, and urea cycle disorders. The use of tandem mass spectrometry (MS/MS) is expanding for the implementation of newborn screening programs for inborn errors of metabolism and for selective screening of children of different ages. In Kazakhstan, the use of MS/MS in metabolic screening programs is not yet developed due to the high cost of equipment and consumables and the lack of special screening centers and specialists. Data on the prevalence of most inborn errors of metabolism in Kazakhstan are not presented in the literature. Aim: to perform selective screening for hereditary metabolic diseases among newborns in western Kazakhstan using the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Methods: Selective screening was performed among 250 newborns with suspected hereditary metabolic disorders using tandem mass spectrometry. Results: The results of selective newborn screening were interpreted by comparison with reference values established for this group. Diagnosis was based on clinical signs, blood levels of amino acids, acylcarnitines, succinylacetone, urine organic acids, and gene mutation tests. An assessment of 37 inborn errors of metabolism frequencies in high-risk newborns was performed. Conclusion: The research will further develop the national as selective as expanded newborn screening programs.

Evaluation of newborn hearing screening results of infants with phenylketonuria

ObjectiveThe purpose of this study is comparing the newborn hearing screening failure rate between phenylketonuria (PKU) infants and matched healthy control infants. Patients and methodsBetween April 2021 and April 2023, data obtained from the national newborn hearing screening program were examined for patients who presented to the pediatric metabolism clinic of Konya City Hospital with a clinical and genetic diagnosis of PKU. A healthy control group, matched for age and gender, was established. The newborn hearing screening test results, demographic information, and pregnancy data of infants with PKU and the control group were compared to assess risk factors. ResultsIn the initial screening test, 23 out of 73 PKU infants (31.5%) and 12 out of 73 infants in the control group (16.4%) failed the test (p = 0.033). Among the 23 PKU infants who did not pass the first test, 9 (35%) also failed the second test and were referred. In contrast, all 12 infants in the control group who did not pass the first test passed the second test. The failure rate in the second test was significantly higher in PKU infants compared to the control group (p = 0.003). It was observed that the maternal age of PKU infants who underwent the second test was significantly higher than that of the control group (p < 0.029). Diagnostic hearing test results were found to be normal in all nine PKU patients who failed the secondary screening test and were referred to a tertiary center. ConclusionIn our study, it was determined that infants with phenylketonuria (PKU) who did not have any risk factors for hearing loss failed the hearing screening test significantly more than healthy infants.

Accurate determination of Biotinidase activity in serum by HPLC and its utilization as second tier test for the confirmation of initial positive newborn screening results

Diagnosis of Biotinidase deficiency (BTD) is extremely important to avoid several neurodevelopmental problems in early childhood. Colorimetric and fluorometric methods lack specificity and selectivity due to several interferences resulting in a high number of false positive results. We developed an HPLC method for BTD activity in serum with fluorescent detection. In colorimetric assays, biotinidase attacks the amide linkage of the artificial substrate biotinidyl-4-aminobenzoic acid (B-PABA) and releases p-aminobenzoic acid (PABA), which is converted to a purple dye by diazotization reaction. The newly developed method injects the reaction mixture directly into the HPLC column and quantifies using a six-point calibration curve without coupling and diazotization reaction. The method is linear over the 5–1000 μmol/L range. The detection and quantitation limits were 2.5 μmol/L and 5.0 μmol/L, respectively. When compared with colorimetric assay, the correlation coefficient (R2) was 0.9963. The within-assay and between-assay precision was <10.0% for four levels of quality control samples. No significant variation in BTD activity was detected due to hemolysis, icteric, and lipemic samples. The newly developed method eliminates the potential interference due to the presence of aromatic amines and significantly reduces the false positive results observed with the colorimetric method. It is simple, specific, sensitive, faster in sample preparation, and requires a small sample volume. The newly developed HPLC method was used in our laboratory as a secondary tier test for initial positive BTD samples from newborn screening programs. To our knowledge, no similar HPLC method has been reported to date.