Efficacy and safety of sapropterin before and during pregnancy: Final analysis of the Kuvan® Adult Maternal Paediatric European Registry (KAMPER) maternal and Phenylketonuria Developmental Outcomes and Safety (PKUDOS) PKU-MOMs sub-registries.

Infants born to mothers with phenylketonuria (PKU) may develop congenital abnormalities because of elevated phenylalanine (Phe) levels in the mother during pregnancy. Maintenance of blood Phe levels between 120 and 360 µmol/L reduces risks of birth defects. Sapropterin dihydrochloride helps maintain blood Phe control, but there is limited evidence on its risk-benefit ratio when used during pregnancy. Data from the maternal sub-registries-KAMPER (NCT01016392) and PKUDOS (NCT00778206; PKU-MOMs sub-registry)-were collected to assess the long-term safety and efficacy of sapropterin in pregnant women in a real-life setting. Pregnancy and infant outcomes, and the safety of sapropterin were assessed. Final data from 79 pregnancies in 57 women with PKU are reported. Sapropterin dose was fairly constant before and during pregnancy, with blood Phe levels maintained in the recommended target range during the majority (82%) of pregnancies. Most pregnancies were carried to term, and the majority of liveborn infants were reported as 'normal' at birth. Few adverse and serious adverse events were considered related to sapropterin, with these occurring in participants with high blood Phe levels. This report represents the largest population of pregnant women with PKU exposed to sapropterin. Results demonstrate that exposure to sapropterin during pregnancy was well-tolerated and facilitated maintenance of blood Phe levels within the target range, resulting in normal delivery. This critical real-world data may facilitate physicians and patients to make informed treatment decisions about using sapropterin in pregnant women with PKU and in women of childbearing age with PKU who are responsive to sapropterin.

Addition of MPS-II to the Recommended Uniform Screening Panel in the United States.

It has recently been announced that the Secretary of the U.S. Department of Health and Human Services has approved the recommendation by the Advisory Committee on Heritable Disorders in Newborns and Children (ACHDNC) to add mucopolysaccharidosis type II (MPS-II, Hunter Syndrome) to the recommended uniform screening panel (RUSP) in the United States [...].

A multinational study of acute and long-term outcomes of Type 1 galactosemia patients who carry the S135L (c.404C > T) variant of GALT.

Patients with galactosemia who carry the S135L (c.404C > T) variant of galactose-1-P uridylyltransferase (GALT), documented to encode low-level residual GALT activity, have been under-represented in most prior studies of outcomes in Type 1 galactosemia. What is known about the acute and long-term outcomes of these patients, therefore, is based on very limited data. Here, we present a study comparing acute and long-term outcomes of 12 patients homozygous for S135L, 25 patients compound heterozygous for S135L, and 105 patients homozygous for two GALT-null (G) alleles. This is the largest cohort of S135L patients characterized to date. Acute disease following milk exposure in the newborn period was common among patients in all 3 comparison groups in our study, as were long-term complications in the domains of speech, cognition, and motor outcomes. In contrast, while at least 80% of both GALT-null and S135L compound heterozygous girls and women showed evidence of an adverse ovarian outcome, prevalence was only 25% among S135L homozygotes. Further, all young women in this study with even one copy of S135L achieved spontaneous menarche; this is true for only about 33% of women with classic galactosemia. Overall, we observed that while most long-term outcomes trended milder among groups of patients with even one copy of S135L, many individual patients, either homozygous or compound heterozygous for S135L, nonetheless experienced long-term outcomes that were not mild. This was true despite detection by newborn screening and both early and life-long dietary restriction of galactose. This information should empower more evidence-based counseling for galactosemia patients with S135L.

Population-Based Screening of Newborns: Findings From the NBS Expansion Study (Part One).

Each year, through population-based newborn screening (NBS), 1 in 294 newborns is identified with a condition leading to early treatment and, in some cases, life-saving interventions. Rapid advancements in genomic technologies to screen, diagnose, and treat newborns promise to significantly expand the number of diseases and individuals impacted by NBS. However, expansion of NBS occurs slowly in the United States (US) and almost always occurs condition by condition and state by state with the goal of screening for all conditions on a federally recommended uniform panel. The Newborn Screening Translational Research Network (NBSTRN) conducted the NBS Expansion Study to describe current practices, identify expansion challenges, outline areas for improvement in NBS, and suggest how models could be used to evaluate changes and improvements. The NBS Expansion Study included a workshop of experts, a survey of clinicians, an analysis of data from online repositories of state NBS programs, reports and publications of completed pilots, federal committee reports, and proceedings, and the development of models to address the study findings. This manuscript (Part One) reports on the design, execution, and results of the NBS Expansion Study. The Study found that the capacity to expand NBS is variable across the US and that nationwide adoption of a new condition averages 9.5 years. Four factors that delay and/or complicate NBS expansion were identified. A companion paper (Part Two) presents a use case for each of the four factors and highlights how modeling could address these challenges to NBS expansion.

Clinical Effectiveness of Telemedicine-Based Pediatric Genetics Care.

BACKGROUND AND OBJECTIVES: Telemedicine may increase access to medical genetics care. However, in the pediatric setting, how telemedicine may affect the diagnostic rate is unknown, partially because of the perceived importance of the dysmorphology physical examination. We studied the clinical effectiveness of telemedicine for patients with suspected or confirmed genetic conditions. METHODS: We conducted a retrospective cohort study of outpatient encounters before and after the widespread implementation of telemedicine (N = 5854). Visit types, diagnoses, patient demographic characteristics, and laboratory data were acquired from the electronic health record. Patient satisfaction was assessed through survey responses. New molecular diagnosis was the primary end point. RESULTS: Patients seen by telemedicine were more likely to report non-Hispanic White ancestry, prefer to speak English, live in zip codes with higher median incomes, and have commercial insurance (all P < .01). Genetic testing was recommended for more patients evaluated by telemedicine than in person (79.5% vs 70.9%; P < .001). Patients seen in person were more likely to have a sample collected, resulting in similar test completion rates (telemedicine, 51.2%; in person, 55.1%; P = .09). There was no significant difference in molecular diagnosis rate between visit modalities (telemedicine, 13.8%; in person, 12.4%; P = .40). CONCLUSIONS: Telemedicine and traditional in-person evaluation resulted in similar molecular diagnosis rates. However, improved methodologies for remote sample collection may be required. This study reveals the feasibility of telemedicine in a large academic medical genetics practice and is applicable to other pediatric specialties with perceived importance of physical examination.

The current state of adult metabolic medicine in the United States: Results of a nationwide survey.

PURPOSE: Patients with inherited metabolic disorders (IMDs) now have improved health outcomes and increased survival into adulthood. There is scant evidence on managing adults with IMDs. We present an analysis of current care practices for adults with IMDs in the United States. METHODS: We created and distributed an online survey to US members of the Society of Inherited Metabolic Disorders. The survey addressed ambulatory care, acute management, and health care transition (HCT) practices of adults with IMDs. RESULTS: The survey was completed by 91 providers from 73 institutions. Most adult patients with IMDs receive lifelong care from a single metabolic clinician, predominantly in pediatric clinic settings. Adults receive comprehensive ambulatory metabolic care, but fewer trainees participate compared with pediatric visits. Most acute IMD management occurs in pediatric hospitals. Clinician comfort with HCT increased the frequency of HCT planning. Overall, all respondents felt that providing specialized care to adults with IMDs is high value. CONCLUSION: Our survey demonstrates the paucity of clinical resources dedicated to adult metabolic medicine. Care is fragmented and varies by medical system. Interest in HCT is robust but would benefit from standardized practices. Our findings reinforce the need for greater focus on adult metabolic medicine in the United States.

Newborn Screening for X-Linked Adrenoleukodystrophy: Review of Data and Outcomes in Pennsylvania.

X-linked adrenoleukodystrophy (X-ALD) is the most common peroxisomal disorder. It results from pathogenic variants in ABCD1, which encodes the peroxisomal very-long-chain fatty acid transporter, causing a spectrum of neurodegenerative phenotypes. The childhood cerebral form of the disease is particularly devastating. Early diagnosis and intervention improve outcomes. Because newborn screening facilitates identification of at-risk individuals during their asymptomatic period, X-ALD was added to the Pennsylvania newborn screening program in 2017. We analyzed outcomes from the first four years of X-ALD newborn screening, which employed a two-tier approach and reflexive ABCD1 sequencing. There were 51 positive screens with elevated C26:0-lysophosphatidylcholine on second-tier screening. ABCD1 sequencing identified 21 hemizygous males and 24 heterozygous females, and clinical follow up identified four patients with peroxisomal biogenesis disorders. There were two false-positive cases and one false-negative case. Three unscreened individuals, two of whom were symptomatic, were diagnosed following their young siblings' newborn screening results. Combined with experiences from six other states, this suggests a U.S. incidence of roughly 1 in 10,500, higher than had been previously reported. Many of these infants lack a known family history of X-ALD. Together, these data highlight both the achievements and challenges of newborn screening for X-ALD.

The diagnosis and management of Gaucher disease in pediatric patients: Where do we go from here?

Gaucher disease (GD) is an autosomal recessive inherited lysosomal storage disease that often presents in early childhood and is associated with damage to multiple organ systems. Many challenges associated with GD diagnosis and management arise from the considerable heterogeneity of disease presentations and natural history. Phenotypic classification has traditionally been based on the absence (in type 1 GD) or presence (in types 2 and 3 GD) of neurological involvement of varying severity. However, patient management and prediction of prognosis may be best served by a dynamic, evolving definition of individual phenotype rather than by a rigid system of classification. Patients may experience considerable delays in diagnosis, which can potentially be reduced by effective screening programs; however, program implementation can involve ethical and practical challenges. Variation in the clinical course of GD and an uncertain prognosis also complicate decisions concerning treatment initiation, with differing stakeholder perspectives around efficacy and acceptable cost/benefit ratio. We review the challenges faced by physicians in the diagnosis and management of GD in pediatric patients. We also consider future directions and goals, including acceleration of accurate diagnosis, improvements in the understanding of disease heterogeneity (natural history, response to treatment, and prognosis), the need for new treatments to address unmet needs for all forms of GD, and refinement of the tools for monitoring disease progression and treatment efficacy, such as specific biomarkers.

Epimutations in both the TESK2 and MMACHC promoters in the Epi-cblC inherited disorder of intracellular metabolism of vitamin B12.

BACKGROUND: epi-cblC is a recently discovered inherited disorder of intracellular vitamin B12 metabolism associating hematological, neurological, and cardiometabolic outcomes. It is produced by an epimutation at the promoter common to CCDC163P and MMACHC, which results from an aberrant antisense transcription due to splicing mutations in the antisense PRDX1 gene neighboring MMACHC. We studied whether the aberrant transcription produced a second epimutation by encompassing the CpG island of the TESK2 gene neighboring CCDC163P. METHODS: We unraveled the methylome architecture of the CCDC163P-MMACHC CpG island (CpG:33) and the TESK2 CpG island (CpG:51) of 17 epi-cblC cases. We performed an integrative analysis of the DNA methylome profiling, transcriptome reconstruction of RNA-sequencing (RNA-seq), chromatin immunoprecipitation sequencing (ChIP-Seq) of histone H3, and transcription expression of MMACHC and TESK2. RESULTS: The PRDX1 splice mutations and activation of numerous cryptic splice sites produced antisense readthrough transcripts encompassing the bidirectional MMACHC/CCDC163P promoter and the TESK2 promoter, resulting in the silencing of both the MMACHC and TESK2 genes through the deposition of SETD2-dependent H3K36me3 marks and the generation of epimutations in the CpG islands of the two promoters. CONCLUSIONS: The antisense readthrough transcription of the mutated PRDX1 produces an epigenetic silencing of MMACHC and TESK2. We propose using the term 'epi-digenism' to define this epigenetic disorder that affects two genes. Epi-cblC is an entity that differs from cblC. Indeed, the PRDX1 and TESK2 altered expressions are observed in epi-cblC but not in cblC, suggesting further evaluating the potential consequences on cancer risk and spermatogenesis.

Perceptions and use of phenylbutyrate metabolite testing in urea cycle disorders: Results of a clinician survey and analysis of a centralized testing database.

The nitrogen scavengers sodium and glycerol phenylbutyrate (PB), approved for chronic treatment of urea cycle disorders (UCDs), undergo hepatic conversion to phenylacetate (PAA), which conjugates glutamine to form phenylacetylglutamine for urinary nitrogen excretion. Elevated PAA has been associated with reversible neurological toxicity, with symptoms similar to hyperammonemia. Plasma PB metabolite analysis can assess for toxicity and therapeutic drug levels. An online survey was undertaken to assess US clinician perceptions and use of the test in addition to an analysis of centralized US laboratory records. Survey responses from 52 clinicians were analyzed, including 58% who reported using plasma PB metabolite testing. Test users reported managing more UCD patients than nonusers. Users rated the test as "often helpful" for ruling out PAA toxicity (44%), informing PB dosing decisions (42%), and assessing adherence (28%). Test results were reported as most often unremarkable (61%) or suggestive of poor adherence (13%); 46% of users had never encountered results indicative of PAA toxicity. Analyses of laboratory records for 1668 plasma metabolite tests determined that only 5% of samples had plasma PAA-to-phenylacetylglutamine ratios associated with increased risk of PAA toxicity. Nearly half of surveyed clinicians were unsure of metabolite targets; those conducting ad hoc (versus regular) testing were significantly more likely to be unsure of targets. One-fifth of test users identified uncertainties, including questions about test validation, timing, and interpretation. Increased awareness of published PB metabolite data and further clinician education on test interpretation may help to inform the use of metabolite testing to optimize UCD care.

The Editor's Choice for Issue 2, Volume 7.

Dear readers: I am proud to say that we are continuing to publish many important papers on newborn screening in IJNS, and the papers published in this issue clearly support my statement [...].

Provider Perspectives on the Impact of the COVID-19 Pandemic on Newborn Screening.

The onset of the COVID-19 pandemic caused significant changes in healthcare delivery. Telemedicine rapidly and unexpectedly became the primary vehicle for ambulatory management. As newborn screen (NBS) referrals require varying levels of acuity, whether telemedicine could be used as a safe and effective medium to return these results were unknown. We sent an online survey to metabolism providers internationally to investigate triage differences of abnormal NBS results during the COVID-19 pandemic. The survey compared personal practice for the periods of March-June 2019 and March-June 2020. Responses were received from 44 providers practicing in 8 countries. Nearly all (93%) practiced in areas of widespread SARS-COV-2 community transmission during spring 2020. There was a significant expansion of telemedicine use for NBS referrals at the onset of the COVID-19 pandemic (OR: 12, 95% CI: 3.66-39.3, p < 0.0001). Telehealth primarily replaced in-person ambulatory metabolism visits. The increased frequency of virtual care was similar across NBS analytes. Providers found telehealth for NBS referral equally efficacious to in-person care. Institutional patient surveys showed no difference in satisfaction with provider communication, provider empathy, or appointment logistics. Our survey was limited by unprecedented disruption in healthcare delivery, necessitating further validation of telegenetics for NBS in the post-pandemic era. Nevertheless, our findings demonstrate that telemedicine is potentially a viable and practical tool for triaging abnormal NBS results.

Should patients with Phosphomannomutase 2-CDG (PMM2-CDG) be screened for adrenal insufficiency?

PMM2-CDG is the most common congenital disorder of glycosylation (CDG) accounting for almost 65% of known CDG cases affecting N-glycosylation. Abnormalities in N-glycosylation could have a negative impact on many endocrine axes. There is very little known on the effect of impaired N-glycosylation on the hypothalamic-pituitary-adrenal axis function and whether CDG patients are at risk of secondary adrenal insufficiency and decreased adrenal cortisol production. Cortisol and ACTH concentrations were simultaneously measured between 7:44 am to 1 pm in forty-three subjects (20 female, median age 12.8 years, range 0.1 to 48.6 years) participating in an ongoing international, multi-center Natural History study for PMM2-CDG (ClinicalTrials.gov Identifier: NCT03173300). Of the 43 subjects, 11 (25.6%) had cortisol below 5 µg/dl and low to normal ACTH levels, suggestive of secondary adrenal insufficiency. Two of the 11 subjects have confirmed central adrenal insufficiency and are on hydrocortisone replacement and/or stress dosing during illness; 3 had normal and 1 had subnormal cortisol response to ACTH low-dose stimulation test but has not yet been started on therapy; the remaining 5 have upcoming stimulation testing planned. Our findings suggest that patients with PMM2-CDG may be at risk for adrenal insufficiency. Monitoring of morning cortisol and ACTH levels should be part of the standard care in patients with PMM2-CDG.

[13C]-galactose breath test in a patient with galactokinase deficiency and spastic diparesis.

Galactokinase deficiency is an inborn error of carbohydrate metabolism due to a block in the formation of galactose-1-phosphate from galactose. Although the association of galactokinase deficiency with formation of cataracts is well established, the extent of the clinical phenotype is still under investigation. We describe a 6-year-old female who was diagnosed with galactokinase deficiency due to cataract formation when she was 10 months of age and initially started on galactose-restricted diet at that time for 5 months. She developed gait abnormality at 4 years of age. Breath tests via measurement of 13C isotope in exhaled carbon dioxide following 13C-labeled galactose administration at carbon-1 and carbon-2 positions revealed oxidation rates within the normal range. The results in this patient strikingly contrast with the results of another patient with GALK1 deficiency that underwent breath testing with [1-14C]-galactose and [2-14C]-galactose. Extension of in vivo breath tests to other galactokinase patients is needed to better understand the pathophysiology of this disease.

Transforming the clinical outcome in CRIM-negative infantile Pompe disease identified via newborn screening: the benefits of early treatment with enzyme replacement therapy and immune tolerance induction.

PURPOSE: To assess the magnitude of benefit to early treatment initiation, enabled by newborn screening or prenatal diagnosis, in patients with cross-reactive immunological material (CRIM)-negative infantile Pompe disease (IPD), treated with enzyme replacement therapy (ERT) and prophylactic immune tolerance induction (ITI) with rituximab, methotrexate, and intravenous immunoglobulin (IVIG). METHODS: A total of 41 CRIM-negative IPD patients were evaluated. Among patients who were treated with ERT + ITI (n = 30), those who were invasive ventilator-free at baseline and had ≥6 months of follow-up were stratified based on age at treatment initiation: (1) early (≤4 weeks), (2) intermediate (>4 and ≤15 weeks), and (3) late (>15 weeks). A historical cohort of 11 CRIM-negative patients with IPD treated with ERT monotherapy served as an additional comparator group. RESULTS: Twenty patients were included; five, seven, and eight in early, intermediate, and late treatment groups, respectively. Genotypes were similar across the three groups. Early-treated patients showed significant improvements in left ventricular mass index, motor and pulmonary outcomes, as well as biomarkers creatine kinase and urinary glucose tetrasaccharide, compared with those treated later. CONCLUSION: Our preliminary data suggest that early treatment with ERT + ITI can transform the long-term CRIM-negative IPD phenotype, which represents the most severe end of the Pompe disease spectrum.

Galactokinase deficiency: lessons from the GalNet registry.

PURPOSE: Galactokinase (GALK1) deficiency is a rare hereditary galactose metabolism disorder. Beyond cataract, the phenotypic spectrum is questionable. Data from affected patients included in the Galactosemias Network registry were collected to better characterize the phenotype. METHODS: Observational study collecting medical data of 53 not previously reported GALK1 deficient patients from 17 centers in 11 countries from December 2014 to April 2020. RESULTS: Neonatal or childhood cataract was reported in 15 and 4 patients respectively. The occurrence of neonatal hypoglycemia and infection were comparable with the general population, whereas bleeding diathesis (8.1% versus 2.17-5.9%) and encephalopathy (3.9% versus 0.3%) were reported more often. Elevated transaminases were seen in 25.5%. Cognitive delay was reported in 5 patients. Urinary galactitol was elevated in all patients at diagnosis; five showed unexpected Gal-1-P increase. Most patients showed enzyme activities ≤1%. Eleven different genotypes were described, including six unpublished variants. The majority was homozygous for NM_000154.1:c.82C>A (p.Pro28Thr). Thirty-five patients were diagnosed following newborn screening, which was clearly beneficial. CONCLUSION: The phenotype of GALK1 deficiency may include neonatal elevation of transaminases, bleeding diathesis, and encephalopathy in addition to cataract. Potential complications beyond the neonatal period are not systematically surveyed and a better delineation is needed.

Diagnostic journey and impact of enzyme replacement therapy for mucopolysaccharidosis IVA: a sibling control study.

BACKGROUND: Mucopolysaccharidosis (MPS) IVA, also known as Morquio A syndrome, is a rare autosomal recessive lysosomal storage disorder caused by a deficiency in the enzyme N-acetylgalactosamine-6-sulfatase. Early recognition, diagnosis, and treatment of this progressive, multisystem disease by enzyme replacement therapy (ERT) can lead to improved outcomes and reduced mortality. METHODS: This report documents the diagnostic journey and treatment with ERT of three siblings with MPS IVA. Clinical outcome measures included growth, endurance, imaging, cardiac, respiratory, ophthalmology, and laboratory evaluations. RESULTS: Three siblings, diagnosed at 14.7, 10.1, and 3.2 years of age, demonstrated clinical improvement with weekly infusions of 2.0 mg/kg elosulfase alfa (Vimizim®, BioMarin Pharmaceutical, Novato, CA, USA). Patient 1 (oldest sibling) and Patient 2 (middle sibling) experienced a diagnostic delay of 8 years 7 months and 4 years after symptom onset, respectively. All three patients demonstrated improvements in growth, 6-min walk distance, joint range of motion, and respiratory function after 30 months of ERT. The treatment was well tolerated without any adverse events. CONCLUSIONS: This case series highlights the importance of early recognition of the clinical and imaging findings that are initially subtle in MPS IVA. Early treatment with ERT is necessary to slow irreversible disease progression and improve patient outcomes. The oldest sibling experienced improvements in mobility despite severe symptoms resulting from a late diagnosis. When evaluating patients with skeletal anomalies, imaging multiple body regions is recommended. When findings such as anterior beaking of vertebrae or bilateral femoral head dysplasia are present, MPS IVA should be included in the differential diagnosis. Newborn screening must be considered for early detection, accurate diagnosis, and initiation of treatment to reduce morbidity.

Person Ability Scores as an Alternative to Norm-Referenced Scores as Outcome Measures in Studies of Neurodevelopmental Disorders.

Although norm-referenced scores are essential to the identification of disability, they possess several features which affect their sensitivity to change. Norm-referenced scores often decrease over time among people with neurodevelopmental disorders who exhibit slower-than-average increases in ability. Further, the reliability of norm-referenced scores is lower at the tails of the distribution, resulting in floor effects and increased measurement error for people with neurodevelopmental disorders. In contrast, the person ability scores generated during the process of constructing a standardized test with item response theory are designed to assess change. We illustrate these limitations of norm-referenced scores, and relative advantages of ability scores, using data from studies of autism spectrum disorder and creatine transporter deficiency.

Newborn Screening for Pompe Disease: Pennsylvania Experience.

Pennsylvania started newborn screening for Pompe disease in February 2016. Between February 2016 and December 2019, 531,139 newborns were screened. Alpha-Glucosidase (GAA) enzyme activity is measured by flow-injection tandem mass spectrometry (FIA/MS/MS) and full sequencing of the GAA gene is performed as a second-tier test in all newborns with low GAA enzyme activity [<2.10 micromole/L/h]. A total of 115 newborns had low GAA enzyme activity and abnormal genetic testing and were referred to metabolic centers. Two newborns were diagnosed with Infantile Onset Pompe Disease (IOPD), and 31 newborns were confirmed to have Late Onset Pompe Disease (LOPD). The incidence of IOPD + LOPD was 1:16,095. A total of 30 patients were compound heterozygous for one pathogenic and one variant of unknown significance (VUS) mutation or two VUS mutations and were defined as suspected LOPD. The incidence of IOPD + LOPD + suspected LOPD was 1: 8431 in PA. We also found 35 carriers, 15 pseudodeficiency carriers, and 2 false positive newborns.