Screening for sickle cell disease: focus on newborn investigations.

Drepanocytosis is a genetic disease relevant for its epidemiological, clinical and socio-economic aspects. In our country the prevalence is highly uneven with peaks in former malaria areas, but migration flows in recent years have led to significant changes. In this document we review the screening programs currently existing in Italy with particular emphasis on newborn screening, which in other countries around the world, including within Europe, is at most universal and mandatory. The essential laboratory issues are reviewed, from sampling aspects (cord blood or peripheral), to the analytical (analytical methods dedicated to neonatal screening and adult carrier detection) and post analytical (reporting, informative) ones. An economic analysis based on data collected in the province of Modena is also proposed, clearly showing that neonatal screening is also beneficial from an economic point of view.

Cell-free DNA screening for fetal aneuploidy using the rolling circle method: A step towards non invasive prenatal testing simplification.

OBJECTIVE: To assess the efficacy of cell-free (cf)DNA screening for aneuploidy using the automated system based on rolling circle replication. METHODS: A prospective study among women referred for invasive prenatal diagnosis between July 2018 and December 2019. The plasma fraction was extracted within 5 days from blood collection, stored at -20°C and cfDNA measured between January and December 2019. RESULTS: A total of 805 women were recruited; 778 with singleton pregnancies and 27 twins. There were 48 Down syndrome, 25 Edwards syndrome and 3 Patau syndrome cases. Overall, the no-call rate was 2.6% (95% confidence interval 1.6%-3.9%) which reduced from 4.7% to 1.1% after relocation of the system (p < 0.002) to ensure a constant ambient temperature below 25°C. In singletons the Down syndrome detection rate (DR) was 100% (93%-100%) and false-positive rate (FPR) 0.14% (0.00%-0.79%). The Edwards syndrome DR was 96% (80%-100%) and FPR 0.78% (0.29%-1.7%). One false-positive had a confined placental trisomy 18 and the remaining five a z-score requiring sample repetition; all the false-positives occurred before system relocation (p < 0.005). Patau syndrome DR and FPR were 67% (9.4%-99%) and 0.26% (0.03%-0.95%). CONCLUSION: The cfDNA rolling circle method yields similar results to other methods provided that room temperature is adequately controlled.

Neonatal Screening for Congenital Hypothyroidism in Preterm Infants: Is a Targeted Strategy Required?

Background: Premature infants are at higher risk of developing congenital hypothyroidism (CH) but the neonatal screening strategy for this population is still debatable. The purpose of this retrospective study is to describe the results of a screening program for CH in a preterm infant cohort. Materials and Methods: All preterm newborns who underwent neonatal screening in the Italian region of Piedmont in the period January 2019-December 2021, were included in this retrospective cohort study. The first thyrotropin (TSH) measurement was performed at 72 hours, whereas the second at 15 days of life. Infants with TSH >20 mUI/L at first detection and >6 mUI/L at second were recalled for a full evaluation of thyroid function. Results: During the study period, 5930 preterm newborns were screened. Based on birthweight (BW), the mean TSH was 2.08 ± 0.15 for BW <1000 g, 2.01 ± 0.02 for BW 1001-1500 g, 2.28 ± 0.03 for BW 1501-2499 g, and 2.41 ± 0.03 mUI/L in normal-weight newborns (p < 0.005) at the first detection, with a significant difference observed at the second measurement (p < 0.005). Based on gestational age, the mean TSH at first detection was 1.71 ± 0.09 mUI/L for extremely preterm babies and 1.87 ± 0.06, 1.94 ± 0.05, and 2.42 ± 0.02 mUI/L for very preterm, moderately, and late preterm infants (p < 0.005), respectively. Significant between-group differences of TSH measurements were also at the second and third detections (p < 0.005 and p = 0.01). The 99% reference range in this cohort overlapped with the recommended TSH cutoffs for screening recall (8 mUI/L for first detection and 6 mUI/L for second detection). CH incidence was 1:156. Of the 38 patients diagnosed with CH, a eutopic gland was present in 30 (87.9%), with CH transient in 29 (76.8%). Conclusions: We observed no significant difference in the recall rate between preterm and at term infants screened in this study. Our current screening strategy therefore appears effective in avoiding misdiagnosis. CH screening approaches vary among countries. Development and testing of a uniform multinational screening strategy is needed.

Expanded Newborn Screening in Italy Using Tandem Mass Spectrometry: Two Years of National Experience.

Newborn screening (NBS) for inborn errors of metabolism is one of the most advanced tools for secondary prevention in medicine, as it allows early diagnosis and prompt treatment initiation. The expanded newborn screening was introduced in Italy between 2016 and 2017 (Law 167/2016; DM 13 October 2016; DPCM 12-1-2017). A total of 1,586,578 infants born in Italy were screened between January 2017 and December 2020. For this survey, we collected data from 15 Italian screening laboratories, focusing on the metabolic disorders identified by tandem mass spectrometry (MS/MS) based analysis between January 2019 and December 2020. Aminoacidemias were the most common inborn errors in Italy, and an equal percentage was observed in detecting organic acidemias and mitochondrial fatty acids beta-oxidation defects. Second-tier tests are widely used in most laboratories to reduce false positives. For example, second-tier tests for methylmalonic acid and homocysteine considerably improved the screening of CblC without increasing unnecessary recalls. Finally, the newborn screening allowed us to identify conditions that are mainly secondary to a maternal deficiency. We describe the goals reached since the introduction of the screening in Italy by exchanging knowledge and experiences among the laboratories.

Longitudinal Monitoring of Alpha-Fetoprotein by Dried Blood Spot for Hepatoblastoma Screening in Beckwith⁻Wiedemann Syndrome.

BACKGROUND: Hepatoblastoma screening in the Beckwith⁻Wiedemann spectrum (BWSp) is currently based on measuring a specific serum marker alpha-fetoprotein (αFP) every three months until the fourth birthday. Frequent blood draws can be a burden for patients and their families. METHODS: We have developed a less invasive alternative testing method based on measuring αFPs from dried blood spots (DBS). The method was validated with 259 simultaneous plasma and DBS αFP measurements in 171 children (132 controls and 39 patients with BWSp). RESULTS: The DBS and plasma measurements overlapped across the wide range of αFP concentrations independent of patient age (p < 0.0001), demonstrating the utility of this method for longitudinal monitoring. Occasional differences between measurements by the two techniques fell within standard laboratory error and would not alter clinical management. CONCLUSIONS: This novel method shows consistent overlap with the traditional blood draws, thereby demonstrating its utility for hepatoblastoma screening in this setting and alleviating the burden of frequent blood draws. This also may help increase patient compliance and reduce costs of health care screening. The DBS-based method for the measurement of cancer biomarkers may also be applied to several other chronic diseases with increased risks of αFP-producing liver tumors.

Neonatal screening for biotinidase deficiency: A 30-year single center experience.

We reviewed the outcome of newborn screening for biotinidase deficiency performed at our department since 1987. Among 1,097,894 newborns screened, 461 were recalled, and 18 were identified as affected by complete or partial biotinidase deficiency (incidence 1:61,000, false positive rate 0.04%). The common missense mutation Q456H was found in 80% of patients with profound biotinidase deficiency. Of them, one patient harbored the novel mutation M399I in compound heterozygosity (M399I/Q456H). The complex allele A171T/D444H in cis was found in two patients with profound biotinidase deficiency (in homozygosity and in compound heterozygosity with the R211H mutation, respectively) and in one patient with partial biotinidase deficiency (in compound heterozygosity with the protective allele D444H in trans). All detected patients were treated and followed up at our Center until present. Biotin therapy (10-20 mg/day) allowed the full prevention of clinical symptoms in all patients with no adverse effects. These excellent outcomes confirm that newborn screening for biotinidase deficiency is a very effective secondary prevention program.