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For patients diagnosed with a rare musculoskeletal or neuromuscular disease, pain may transition from acute to chronic; the latter yielding additional challenges for both patients and care providers. We assessed the present understanding of pain across a set of ten rare, noninfectious, noncancerous disorders; Osteogenesis Imperfecta, Ehlers-Danlos Syndrome, Achondroplasia, Fibrodysplasia Ossificans Progressiva, Fibrous Dysplasia/McCune-Albright Syndrome, Complex Regional Pain Syndrome, Duchenne Muscular Dystrophy, Infantile- and Late-Onset Pompe disease, Charcot-Marie-Tooth Disease, and Amyotrophic Lateral Sclerosis. Through the integration of natural history, cross-sectional, retrospective, clinical trials, & case studies we described pathologic and genetic factors, pain sources, phenotypes, and lastly, existing therapeutic approaches. We highlight that while rare diseases possess distinct core pathologic features, there are a number of shared pain phenotypes and mechanisms that may be prospectively examined and therapeutically targeted in a parallel manner. Finally, we describe clinical and research approaches that may facilitate more accurate diagnosis, monitoring, and treatment of pain as well as elucidation of the evolving nature of pain phenotypes in rare musculoskeletal or neuromuscular illnesses.

Pompe disease results from lysosomal acid α-glucosidase deficiency, which leads to cardiomyopathy in all infantile-onset and occasional late-onset patients. Cardiac assessment is important for its diagnosis and management. This article presents unpublished cardiac findings, concomitant medications, and cardiac efficacy and safety outcomes from the ADVANCE study; trajectories of patients with abnormal left ventricular mass z score at enrolment; and post hoc analyses of on-treatment left ventricular mass and systolic blood pressure z scores by disease phenotype, GAA genotype, and “fraction of life” (defined as the fraction of life on pre-study 160 L production-scale alglucosidase alfa). ADVANCE evaluated 52 weeks’ treatment with 4000 L production-scale alglucosidase alfa in ≥1-year-old United States of America patients with Pompe disease previously receiving 160 L production-scale alglucosidase alfa. M-mode echocardiography and 12-lead electrocardiography were performed at enrolment and Week 52. Sixty-seven patients had complete left ventricular mass z scores, decreasing at Week 52 (infantile-onset patients, change −0.8 ± 1.83; 95% confidence interval −1.3 to −0.2; all patients, change −0.5 ± 1.71; 95% confidence interval −1.0 to −0.1). Patients with “fraction of life” Trial registry: ClinicalTrials.gov Identifier: NCT01526785 https://clinicaltrials.gov/ct2/show/NCT01526785.Social Media Statement: Post hoc analyses of the ADVANCE study cohort of 113 children support ongoing cardiac monitoring and concomitant management of children with Pompe disease on long-term alglucosidase alfa to functionally improve cardiomyopathy and/or dysrhythmia.

International audience; The ALF transcription factor paralogs, AFF1, AFF2, AFF3, and AFF4, are components of the transcriptional super elongation complex that regulates expression of genes involved in neurogenesis and development. We describe an autosomal dominant disorder associated with de novo missense variants in the degron of AFF3, a nine amino acid sequence important for its binding to ubiquitin ligase, or with de novo deletions of this region. The sixteen affected individuals we identified, along with two previously reported individuals, present with a recognizable pattern of anomalies, which we named KINSSHIP syndrome (KI for horseshoe kidney, NS for Nievergelt/Savarirayan type of mesomelic dysplasia, S for seizures, H for hypertrichosis, I for intellectual disability, and P for pulmonary involvement), partially overlapping the AFF4-associated CHOPS syndrome. Whereas homozygous Aff3 knockout mice display skeletal anomalies, kidney defects, brain malformations, and neurological anomalies, knockin animals modeling one of the microdeletions and the most common of the missense variants identified in affected individuals presented with lower mesomelic limb deformities like KINSSHIP-affected individuals and early lethality, respectively. Overexpression of AFF3 in zebrafish resulted in body axis anomalies, providing some support for the pathological effect of increased amount of AFF3. The only partial phenotypic overlap of AFF3-and AFF4-associated syndromes and the previously published transcriptome analyses of ALF transcription factors suggest that these factors are not redundant and each contributes uniquely to proper development.

Contains fulltext : 229474.pdf (Publisher’s version ) (Open Access) Phosphoglucomutase 1 deficiency is a congenital disorder of glycosylation (CDG) with multiorgan involvement affecting carbohydrate metabolism, N-glycosylation and energy production. The metabolic management consists of dietary D-galactose supplementation that ameliorates hypoglycemia, hepatic dysfunction, endocrine anomalies and growth delay. Previous studies suggest that D-galactose administration in juvenile patients leads to more significant and long-lasting effects, stressing the urge of neonatal diagnosis (0-6 months of age). Here, we detail the early clinical presentation of PGM1-CDG in eleven infantile patients, and applied the modified Beutler test for screening of PGM1-CDG in neonatal dried blood spots (DBSs). All eleven infants presented episodic hypoglycemia and elevated transaminases, along with cleft palate and growth delay (10/11), muscle involvement (8/11), neurologic involvement (5/11), cardiac defects (2/11). Standard dietary measures for suspected lactose intolerance in four patients prior to diagnosis led to worsening of hypoglycemia, hepatic failure and recurrent diarrhea, which resolved upon D-galactose supplementation. To investigate possible differences in early vs. late clinical presentation, we performed the first systematic literature review for PGM1-CDG, which highlighted respiratory and gastrointestinal symptoms as significantly more diagnosed in neonatal age. The modified Butler-test successfully identified PGM1-CDG in DBSs from seven patients, including for the first time Guthrie cards from newborn screening, confirming the possibility of future inclusion of PGM1-CDG in neonatal screening programs. In conclusion, severe infantile morbidity of PGM1-CDG due to delayed diagnosis could be prevented by raising awareness on its early presentation and by inclusion in newborn screening programs, enabling early treatments and galactose-based metabolic management.

Pompe disease results from lysosomal acid α-glucosidase (GAA) deficiency and its associated glycogen accumulation and muscle damage. Alglucosidase alfa (recombinant human GAA (rhGAA)) received approval in 2006 as a treatment for Pompe disease at the 160 L production scale. In 2010, larger-scale rhGAA was approved for patients up to 8 years old without cardiomyopathy. NCT01526785 evaluated 4,000 L rhGAA efficacy/safety in US infantile- or late-onset Pompe disease (IOPD, LOPD) patients up to 1 year old transitioned from 160 L rhGAA. A total of 113 patients (87 with IOPD; 26 with LOPD) received 4,000 L rhGAA for 52 weeks dosed the same as previous 160 L rhGAA. Efficacy was calculated as the percentage of patients stable/improved at week 52 (without death, new requirement for invasive ventilation, left ventricular mass z-score increase >1 if baseline was >2, upright forced vital capacity decrease ≥15% predicted, or Gross Motor Function Measure–88 decrease ≥8 percentage points). Safety evaluation included an extension ≤20 months. Week 52 data was available for 104 patients, 100 of whom entered the extension. At week 52, 87/104 (83.7%) were stable/improved. Overall survival was 98.1% overall, 97.6% IOPD, 100% LOPD; 92.4% remained invasive ventilator–free (93.4% IOPD, 88.7% LOPD). Thirty-five patients had infusion-associated reactions. Eight IOPD patients died of drug-unrelated causes. Most Pompe disease patients were clinically stable/improved after transitioning to 4,000 L rhGAA. Safety profiles of both rhGAA forms were consistent.

Current approaches to detect and characterize mosaic chromosomal aneuploidy are limited by sensitivity, efficiency, cost, or the need to culture cells. We describe the mosaic aneuploidy detection by massively parallel sequencing (MAD-seq) capture assay and the MADSEQ analytical approach that allow low (MADSEQ analytical approach can be applied to exome or whole-genome sequencing data, revealing previously unrecognized aneuploidy or copy number neutral loss of heterozygosity in samples studied by the 1000 Genomes Project, cell lines from public repositories, and one of the Illumina Platinum Genomes samples. We have made the meMAD-seq capture design and MADSEQ analytical software open for unrestricted use, with the goal that they can be applied in clinical samples to allow new insights into the unrecognized prevalence of mosaic chromosomal aneuploidy in humans and its phenotypic associations.

Fucosyltransferase 8 (FUT8) encodes a Golgi-localized α1,6 fucosyltransferase that is essential for transferring the monosaccharide fucose into N-linked glycoproteins, a process known as "core fucosylation." Here we describe three unrelated individuals, who presented with intrauterine growth retardation, severe developmental and growth delays with shortened limbs, neurological impairments, and respiratory complications. Each underwent whole-exome sequencing and was found to carry pathogenic variants in FUT8. The first individual (consanguineous family) was homozygous for c.715C>T (p.Arg239∗), while the second (non-consanguineous family) was compound heterozygous for c.1009C>G (p.Arg337Gly) and a splice site variant c.1259+5G>T. The third individual (consanguineous family) was homozygous for a c.943C>T (p.Arg315∗). Splicing analysis confirmed the c.1259+5G>T resulted in expression of an abnormal FUT8 transcript lacking exon 9. Functional studies using primary fibroblasts from two affected individuals revealed a complete lack of FUT8 protein expression that ultimately resulted in substantial deficiencies in total core fucosylated N-glycans. Furthermore, serum samples from all three individuals showed a complete loss of core fucosylation. Here, we show that loss of function mutations in FUT8 cause a congenital disorder of glycosylation (FUT8-CDG) characterized by defective core fucosylation that phenotypically parallels some aspects of the Fut8-/- knockout mouse. Importantly, identification of additional affected individuals can be easily achieved through analysis of core fucosylation of N-glycans.

Early infantile Krabbe disease is rapidly fatal, but hematopoietic stem cell transplantation (HSCT) may improve outcomes if performed soon after birth. New York State began screening all newborns for Krabbe disease in 2006. Infants with abnormal newborn screen results for Krabbe disease were referred to specialty-care centers. Newborns found to be at high risk for Krabbe disease underwent a neurodiagnostic battery to determine the need for emergent HSCT. Almost 2 million infants were screened. Five infants were diagnosed with early infantile Krabbe disease. Three died, two from HSCT-related complications and one from untreated disease. Two children who received HSCT have moderate to severe developmental delays. Forty-six currently asymptomatic children are considered to be at moderate or high risk for development of later-onset Krabbe disease. These results show significant HSCT-associated morbidity and mortality in early infantile Krabbe disease and raise questions about its efficacy when performed in newborns diagnosed through newborn screening. The unanticipated identification of “at risk” children introduces unique ethical and medicolegal issues. New York’s experience raises questions about the risks, benefits, and practicality of screening newborns for Krabbe disease. It is imperative that objective assessments be made on an ongoing basis as additional states begin screening for this disorder. Genet Med 18 12, 1235–1243.

The ALF transcription factor paralogs,AFF1, AFF2, AFF3andAFF4, are components of the transcriptional super elongation complex that regulates expression of genes involved in neurogenesis and development. We describe a new autosomal dominant disorder associated withde novomissense variants in the degron of AFF3, a nine amino acid sequence important for its degradation. Consistent with a causative role ofAFF3variants, the mutated AFF3 proteins show reduced clearance. Ten affected individuals were identified, and present with a recognizable pattern of anomalies, which we named KINSSHIP syndrome (KI for horseshoeKIdney, NS forNievergelt/Savarirayan type of mesomelic dysplasia, S forSeizures, H forHypertrichosis, I forIntellectual disability and P forPulmonary involvement), partially overlapping theAFF4associated CHOPS syndrome. An eleventh individual with a microdeletion encompassing only the transactivation domain and degron motif ofAFF3exhibited overlapping clinical features. A zebrafish overexpression model that shows body axis anomalies provides further support for the pathological effect of increased amount of AFF3 protein.Whereas homozygousAff3knockout mice display skeletal anomalies, kidney defects, brain malformation and neurological anomalies, knock-in animals modeling the microdeletion and the missense variants identified in affected individuals presented with lower mesomelic limb deformities and early lethality, respectively.Transcriptome analyses as well as the partial phenotypic overlap of syndromes associated withAFF3andAFF4variants suggest that ALF transcription factors are not redundant in contrast to what was previously suggested

Introduction There is limited understanding of relationships between genotype, phenotype and other conditions contributing to health in neonates with medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD) identified through newborn screening. Methods Retrospective analysis of comprehensive data from a cohort of 221 newborn-screened subjects identified as affected with MCADD in the Inborn Errors of Metabolism – Information System (IBEM-IS), a long term follow-up database of the Inborn Errors of Metabolism Collaborative, was performed. Results The average age at notification of first newborn screen results to primary care or metabolic providers was 7.45 days. The average octanoylcarnitine (C8) value on first newborn screen was 11.2 μmol/L (median 8.6, range 0.36–43.91). A higher C8 level correlated with an earlier first subspecialty visit. Subjects with low birth weight had significantly lower C8 values. Significantly higher C8 values were found in symptomatic newborns, in newborns with abnormal lab testing in addition to newborn screening and/or diagnostic tests, and in subjects homozygous for the c.985A > G ACADM gene mutation or compound heterozygous for the c.985A > G mutation and deletions or other known highly deleterious mutations. Subjects with neonatal symptoms, or neonatal abnormal labs, or neonatal triggers were more likely to have at least one copy of the severe c.985A > G ACADM gene mutation. C8 and genotype category were significant predictors of the likelihood of having neonatal symptoms. Neonates with select triggers were more likely to have symptoms and laboratory abnormalities. Conclusions This collaborative study is the first in the United States to describe health associations of a large cohort of newborn-screened neonates identified as affected with MCADD. The IBEM-IS has utility as a platform to better understand the characteristics of individuals with newborn-screened conditions and their follow-up interactions with the health system.

Graphical abstract key: ADHD, attention deficit hyperactivity disorder; ASD, atrial septal defect; DD, developmental delay; EEG, electroencephalogram; Ht, height; ID, intellectual disability; OCD, obsessive-compulsive disorder; OFC, open fontanelle; PDA, patent ductus arteriosis; PFO, patent foramen ovale; VSD, ventricular septal defect; Wt, weight.

Unexplained childhood fracture(s) warrant consideration of physical abuse and osteogenesis imperfecta (OI). Genetic OI testing may identify “variants of unknown significance (VUS).” Interpretation of VUS in context of potential abuse may have protective, criminal, and medical impacts. This case series explores practices regarding clinicians' interpretation of VUS during child abuse evaluations. Variability was noted regarding factors considered for interpreting clinical significance. Based on these cases, recommendations for careful and thorough evaluation are detailed, including proposed use of a limited follow-up skeletal survey in 3 months, as a consideration to assess healing of prior fractures and to look for any additional injuries.

Purpose To describe a diagnostic protocol, surveillance and treatment guidelines, genetic counseling considerations and long-term follow-up data elements developed in preparation for X-linked adrenoleukodystrophy (X-ALD) newborn screening in New York State. Methods A group including the director from each regional NYS inherited metabolic disorder center, personnel from the NYS Newborn Screening Program, and others prepared a follow-up plan for X-ALD NBS. Over the months preceding the start of screening, a series of conference calls took place to develop and refine a complete newborn screening system from initial positive screen results to long-term follow-up. Results A diagnostic protocol was developed to determine for each newborn with a positive screen whether the final diagnosis is X-ALD, carrier of X-ALD, Zellweger spectrum disorder, acyl CoA oxidase deficiency or D-bifunctional protein deficiency. For asymptomatic males with X-ALD, surveillance protocols were developed for use at the time of diagnosis, during childhood and during adulthood. Considerations for timing of treatment of adrenal and cerebral disease were developed. Conclusion Because New York was the first newborn screening laboratory to include X-ALD on its panel, and symptoms may not develop for years, long-term follow-up is needed to evaluate the presented guidelines.

BACKGROUND Cross-reactive immunological material-negative (CRIM-negative) infantile Pompe disease (IPD) patients develop an immune response against enzyme replacement therapy (ERT) with alglucosidase alfa that nullifies ERT efficacy. Prophylactic immune tolerance induction (ITI) with rituximab, methotrexate, and IVIG successfully prevents development of deleterious rhGAA IgG antibodies; however, safety, likelihood of success, and long-term efficacy of ITI in a larger cohort remain unknown. METHODS Clinical data were analyzed for 19 CRIM-negative IPD patients who received ITI with rituximab, methotrexate, and IVIG in the ERT-naive setting (ERT+ITI) and compared to a historical cohort of 10 CRIM-negative IPD patients on ERT monotherapy. RESULTS ITI was safely tolerated, although infections were reported in 4 patients. Fourteen (74%) ERT+ITI patients were alive, with a median age of 44.2 months at their final assessment. The eldest survivor was 103.9 months old, with 100.2 months of follow-up after initiation of ERT+ITI. Death (n = 5) occurred at a median age of 29.2 months and was unrelated to the administration of ITI. Fifteen patients either did not seroconvert (n = 8) or maintained low titers (n = 7; defined as titers of ≤6,400 throughout the course of ERT) following ERT+ITI. Only one patient developed high and sustained antibody titers (defined as titers of ≥51,200 at or beyond 6 months on ERT). Left ventricular mass index (LVMI) decreased from a median of 248.5 g/m2 at baseline to 76.8 g/m2 at a median time from ERT+ITI initiation to 59 weeks. ERT+ITI significantly improved overall survival (P = 0.001), eliminated/reduced antibodies at values of ≤6,400 at week 52 on ERT (P = 0.0004), and improved LVMI at week 52 on ERT (P = 0.02) when compared with ERT monotherapy. CONCLUSION Evidence from this international cohort of CRIM-negative IPD patients further supports the safety, feasibility, and efficacy of ITI in the prevention of immune responses to ERT. TRIAL REGISTRATION Clinicaltrials.gov NCT01665326. FUNDING This research was supported in part by the Lysosomal Disease Network, a part of NIH Rare Diseases Clinical Research Network, and by a grant from Genzyme, a Sanofi company.

Current approaches to detect and characterize mosaic chromosomal aneuploidy are limited by sensitivity, efficiency, cost or the need to culture cells. We describe a combination of a new sequencing-based assay and a novel analytical approach that allows low levels of mosaicism for chromosomal aneuploidy to be detected, assigned to a meiotic or mitotic origin, and quantified as a proportion of the cells in the sample. We show results from a multi-ethnic assay design that is suitable for populations of diverse racial and ethnic origins, and how the MADSEQ analytical approach applied to exome sequencing data reveals unrecognized aneuploidy in 1000 Genomes samples and cell lines from public repositories. We have made the assay design and analytical software open for unrestricted use, with the goal that it can be applied in clinical samples to allow new insights into the unrecognized prevalence of mosaic chromosomal aneuploidy and its phenotypic associations.

After a Pompe disease diagnosis is confirmed in infants identified through newborn screening (NBS), when and if to start treatment with enzyme replacement therapy (ERT) with alglucosidase alfa must be determined. In classic infantile-onset Pompe disease, ERT should start as soon as possible. Once started, regular, routine follow-up is necessary to monitor for treatment effects, disease progression, and adverse effects. Decision-making for when or if to start ERT in late-onset Pompe disease (LOPD) is more challenging because patients typically have no measurable signs or symptoms or predictable time of symptom onset at NBS. With LOPD, adequate, ongoing follow-up and assessments for onset or progression of signs and symptoms are important to track disease state and monitor and adjust care before and after treatment is started. Because numerous tests are used to monitor patients at variable frequencies, a standardized approach across centers is lacking. Significant variability in patient assessments may result in missed opportunities for early intervention. Management of Pompe disease requires a comprehensive, multidisciplinary approach with timely disease-specific interventions that target the underlying disease process and symptom-specific manifestations. Regardless of how identified, all patients who have signs or symptoms of the disease require coordinated medical care and follow-up tailored to individual needs throughout their lives. The Pompe Disease Newborn Screening Working Group identifies key considerations before starting and during ERT; summarizes what comprises an indication to start ERT; and provides guidance on how to determine appropriate patient management and monitoring and guide the frequency and type of follow-up assessments for all patients identified through NBS.

Newborn screening (NBS) for Pompe disease is done through analysis of acid α-glucosidase (GAA) activity in dried blood spots. When GAA levels are below established cutoff values, then second-tier testing is required to confirm or refute a diagnosis of Pompe disease. This article in the “Newborn Screening, Diagnosis, and Treatment for Pompe Disease” guidance supplement provides recommendations for confirmatory testing after a positive NBS result indicative of Pompe disease is obtained. Two algorithms were developed by the Pompe Disease Newborn Screening Working Group, a group of international experts on both NBS and Pompe disease, based on whether DNA sequencing is performed as part of the screening method. Using the recommendations in either algorithm will lead to 1 of 3 diagnoses: classic infantile-onset Pompe disease, late-onset Pompe disease, or no disease/not affected/carrier. Mutation analysis of the GAA gene is essential for confirming the biochemical diagnosis of Pompe disease. For NBS laboratories that do not have DNA sequencing capabilities, the responsibility of obtaining sequencing of the GAA gene will fall on the referral center. The recommendations for confirmatory testing and the initial evaluation are intended for a broad global audience. However, the Working Group recognizes that clinical practices, standards of care, and resource capabilities vary not only regionally, but also by testing centers. Individual patient needs and health status as well as local/regional insurance reimbursement programs and regulations also must be considered.

BackgroundHealth care outcomes have been increasingly assessed through health-related quality of life (HRQoL) measures. While the introduction of nitrogen-scavenging medications has improved survival in patients with urea cycle disorders (UCDs), they are often associated with side effects that may affect patient compliance and outcomes.MethodsSymptoms commonly associated with nitrogen-scavenging medications were evaluated in 100 adult and pediatric participants using a non-validated UCD-specific questionnaire. Patients or their caregivers responded to a pre-defined list of symptoms known to be associated with the use of these medications. Responses were collected at baseline (while patients were receiving sodium phenylbutyrate [NaPBA]) and during treatment with glycerol phenylbutyrate (GPB).ResultsAfter 3 months of GPB dosing, there were significant reductions in the proportion of patients with treatment-associated symptoms (69% vs. 46%; p

Krabbe disease (KD) results from galactocerebrosidase (GALC) deficiency. Infantile KD symptoms include irritability, progressive stiffness, developmental delay, and death. The only potential treatment is hematopoietic stem cell transplantation. New York State (NYS) implemented newborn screening for KD in 2006. Dried blood spots from newborns were assayed for GALC enzyme activity using mass spectrometry, followed by molecular analysis for those with low activity (≤12% of the daily mean). Infants with low enzyme activity and one or more mutations were referred for follow-up diagnostic testing and neurological examination. Of >1.9 million screened, 620 infants were subjected to molecular analysis and 348 were referred for diagnostic testing. Five had enzyme activities and mutations consistent with infantile KD and manifested clinical/neurodiagnostic abnormalities. Four underwent transplantation, two are surviving with moderate to severe handicaps, and two died from transplant-related complications. The significance of many sequence variants identified is unknown. Forty-six asymptomatic infants were found to be at moderate to high risk for disease. The positive predictive value of KD screening in NYS is 1.4% (5/346) considering confirmed infantile cases. The incidence of infantile KD in NYS is approximately 1 in 394,000, but it may be higher for later-onset forms. Genet Med 18 3, 239–248.

Urea cycle disorders (UCD) are rare inborn errors of metabolism which result from mutations in the genes encoding for one of six enzymes or two transporters necessary for normal function of the urea cycle and are characterized by hyperammonemia and life-threatening hyperammonemic crises1,2. Hyperammonemia-related neurologic injury ranges from lethal cerebral edema to mild or subclinical cognitive impairment among individuals with milder genetic defects3. Abnormalities in executive function, manifested by difficulty in goal setting, planning, monitoring progress and purposeful problem solving significantly impair day-to-day function among children with UCDs, even those with milder disease who present beyond the neonatal period4. Management of UCD patients typically involves dietary protein restriction, dietary supplements and, when dietary management alone is insufficient, sodium phenylbutyrate (NaPBA), which is the only approved drug (Ucyclyd Pharma, US trade name: BUPHENYL®, EU: AMMONAPS®) for treatment of UCDs2,5. Glycerol phenylbutyrate is an investigational agent being developed for UCDs 6,7,8. Like NaPBA, it contains phenylbutyric acid (PBA), a pro-drug that is converted via β-oxidation to the active moiety, phenylacetic acid (PAA), which conjugates with glutamine to form phenylacetylglutamine (PAGN). PAGN is excreted in the urine and mediates waste nitrogen excretion. Unlike NaPBA, glycerol phenylbutyrate consists of three molecules of PBA joined to glycerol in ester linkage that is hydrolyzed in the small intestine by pancreatic lipases to release PBA, contains no sodium, has minimal taste and no odor, and 17.4 mL contains the same amount of PBA as 40 tablets of NaPBA, the maximal approved daily dose 6,7,8. The development of glycerol phenylbutyrate for UCD, rare disorders with fewer than 500 patients in the US currently estimated to be treated with NaPBA, has involved a cooperative effort among investigators of the NIH-funded UCD Consortium, the National Urea Cycle Disorders Foundation and Hyperion Therapeutics 2,9,10. This report describes the results of the pivotal phase 3 study of glycerol phenylbutyrate for UCD, as well as short and long-term ammonia control and neurocognitive outcomes among a total of 91 UCD patients participating in four clinical trials.

UnlabelledWe have analyzed pharmacokinetic data for glycerol phenylbutyrate (also GT4P or HPN-100) and sodium phenylbutyrate with respect to possible dosing biomarkers in patients with urea cycle disorders (UCD).Study designThese analyses are based on over 3000 urine and plasma data points from 54 adult and 11 pediatric UCD patients (ages 6-17) who participated in three clinical studies comparing ammonia control and pharmacokinetics during steady state treatment with glycerol phenylbutyrate or sodium phenylbutyrate. All patients received phenylbutyric acid equivalent doses of glycerol phenylbutyrate or sodium phenylbutyrate in a cross over fashion and underwent 24-hour blood samples and urine sampling for phenylbutyric acid, phenylacetic acid and phenylacetylglutamine.ResultsPatients received phenylbutyric acid equivalent doses of glycerol phenylbutyrate ranging from 1.5 to 31.8 g/day and of sodium phenylbutyrate ranging from 1.3 to 31.7 g/day. Plasma metabolite levels varied widely, with average fluctuation indices ranging from 1979% to 5690% for phenylbutyric acid, 843% to 3931% for phenylacetic acid, and 881% to 1434% for phenylacetylglutamine. Mean percent recovery of phenylbutyric acid as urinary phenylacetylglutamine was 66.4 and 69.0 for pediatric patients and 68.7 and 71.4 for adult patients on glycerol phenylbutyrate and sodium phenylbutyrate, respectively. The correlation with dose was strongest for urinary phenylacetylglutamine excretion, either as morning spot urine (r = 0.730, p < 0.001) or as total 24-hour excretion (r = 0.791 p

Context Autosomal dominant inactivating sprouty-related EVH1 domain–containing protein 1 (SPRED1) mutations have recently been described in individuals presenting mainly with cafe au lait macules (CALMs), axillary freckling, and macrocephaly. The extent of the clinical spectrum of this new disorder needs further delineation. Objective To determine the frequency, mutational spectrum, and phenotype of neurofibromatosis type 1–like syndrome (NFLS) in a large cohort of patients. Design, Setting, and Participants In a cross-sectional study, 22 unrelated probands carrying a SPRED1 loss-of-function (LOF) mutation identified through clinical testing participated with their families in a genotype-phenotype study (2007-2008). In a second cross-sectional study, 1318 unrelated anonymous samples collected in 2003-2007 from patients with a broad range of signs typically found in neurofibromatosis type 1 (NF1) but no detectable NF1 germline mutation underwent SPRED1 mutation analysis. Main Outcome Measures Comparison of aggregated clinical features in patients with or without a SPRED1 or NF1 mutation. Functional assays were used to evaluate the pathogenicity of missense mutations. Results Among 40 SPRED1 LOF-positive individuals from the clinical cohort, 20 (50%; 95% confidence interval [CI], 34%-66%) fulfilled National Institutes of Health (NIH) NF1 diagnostic criteria based on the presence of more than 5 CALMs with or without freckling or an NF1-compatible family history. None of the 40 SPRED1 LOF-positive individuals (0%; 95% CI, 0%-7%) had discrete cutaneous or plexiform neurofibromas, typical NF1 osseous lesions, or symptomatic optic pathway gliomas. In the anonymous cohort of 1318 individuals, 34 different SPRED1 mutations in 43 probands were identified: 26 pathogenic mutations in 33 probands and 8 probable nonpathogenic missense or silent mutations in 10 probands. Of 94 probands with familial CALMs with or without freckling and no other NF1 features, 69 (73%; 95% CI, 63%-80%) had an NF1 mutation and 18 (19%; 95% CI, 12%-29%) had a pathogenic SPRED1 mutation. In the anonymous cohort, 1.9% (95% CI, 1.2%-2.9%) of individuals with the clinical diagnosis of NF1 according to the NIH criteria had NFLS. Conclusions A high SPRED1 mutation detection rate was found in NF1 mutation–negative families with an autosomal dominant phenotype of CALMs with or without freckling and no other NF1 features. Among individuals in this study, NFLS was not associated with the peripheral and central nervous system tumors seen in NF1.

Medium chain acyl-CoA dehydrogenase (MCAD) deficiency is one of the most common inborn errors of metabolism. Affected patients have impaired ability to break down medium chain fatty acids during fasting, and typically present in the early years of life with hypoketotic hypoglycemia, Reye syndrome-like symptoms, brain damage or death. The development of newborn screening (NBS) for MCAD deficiency has greatly improved outcome, but some patients still appear at risk for severe complications. We reviewed the outcome of patients identified with MCAD deficiency by the New York State NBS process to identify biochemical or genotypic markers which might predict outcome.All eight NBS follow-up centers in New York State contributed the cases of MCAD deficiency diagnosed by newborn screen, who received diagnostic and follow-up care in their clinic. Data reviewed included gender, age, birthweight, initial NBS octanoylcarnitine level (C8) and C8/C2 ratio, follow-up C8 and hexanoylglycine, race/ethnicity, and presence of neonatal or later symptoms.We identified 53 cases of MCAD deficiency. More than one quarter of patients had a post-neonatal symptomatic admission (predominantly lethargy associated with an intercurrent illness). No genotype or C8 level was protective for neonatal or later symptoms. There was a relationship between initial C8 level or C8/C2 ratio and occurrence of later symptoms (7.3 micromol/L in the asymptomatic vs. 19.1 micromol/L in the symptomatic, p0.0002 for C8, and 0.26 vs. 0.6, respectively, for C8/C2 ratio, p0.012). Four infants had initial C8 level30 micromol/L; these infants had a high rate of symptomatic or multiple symptomatic episodes or a history of sibling death from "SIDS", and typically had deletion, nonsense or splice sites mutations. Infants having a history of a symptomatic episode were more likely to have higher initial C8 on NBS and a genotype predicted to strongly affect protein function. In our ethnically diverse group of patients, the c.985AG mutation was rarely found in non-Caucasians.No genotype or metabolite profile is protective from symptoms. The strong relationship between initial C8 level and outcome suggests that in at least some cases neonates having high initial C8 levels may be demonstrating an increased susceptibility to catabolic stress, and may merit additional precautions. Our data also suggest that these infants are more likely to carry severe mutations including homozygosity for the common mutation, deletions, nonsense or splice site mutations. The reports of significant lethargy or hypoglycemia during intercurrent illness in over one quarter of cases even when early medical intervention is recommended (and even when initial C8 is not profoundly elevated) underscores the importance of continued vigilance to prevent stressful fasting in this disorder.

Inborn errors of fatty acid metabolism are important causes of reversible cardiomyopathy in infancy. Disorders in long chain fatty acid oxidation can lead to cardiomyopathy, as fatty acid beta oxidation is the major source of myocardial energy after birth. We present 2 cases of such disorders with cardiac manifestations during infancy, which responded well to a diet low in long chain fatty acids.

Krabbe disease is a rare inherited neurologic disorder affecting the central and peripheral nervous systems. The disease has four phenotypes: early infantile, later onset, adolescent, and adult. The only known treatment is hematopoietic stem cell transplantation, which is, in the early infantile form of the disease, most beneficial if performed before onset of clinical symptoms. In August 2006, New York State began screening all newborns for Krabbe disease. A rapid and accurate technique for assessing galactocerebrosidase activity and performing DNA mutation analysis had been developed. Interpreting these results was limited, however, because neither enzyme activity nor genetic mutation reliably predicts phenotype. A series of initiatives were therefore developed by a multidisciplinary group of neurologists, geneticists, metabolic pediatricians, neurodevelopmental pediatricians, and transplant physicians (the Krabbe Consortium of New York State) to enhance the effectiveness of the newborn screening program. A standardized clinical evaluation protocol was designed based on the available literature, criteria for transplantation for the early infantile phenotype were formulated, a clinical database and registry was developed, and a study of developmental and functional outcomes was instituted. This multidisciplinary standardized approach to evaluating infants who have positive results on newborn screening may serve as a model for other states as they begin the process of screening for Krabbe disease and other lysosomal storage disorders.

3-MCC deficiency is among the most common inborn errors of metabolism identified on expanded newborn screening (1:36,000 births). However, evidence-based guidelines for diagnosis and management of this disorder are lacking. Using the traditional Delphi method, a panel of 15 experts in inborn errors of metabolism was convened to develop consensus-based clinical practice guidelines for the diagnosis and management of 3-MCC screen-positive infants and their mothers. The Oxford Centre for Evidence-based Medicine system was used to grade the literature review and create recommendations graded from A (evidence level of randomized clinical trials) to D (expert opinion). Panelists reviewed the initial evaluation of the screen-positive infant-mother dyad, diagnostic guidelines, and management of diagnosed patients. Grade D consensus recommendations were made in each of these three areas. The panel did not reach consensus on all issues. This consensus protocol is intended to assist clinicians in the diagnosis and management of screen-positive newborns for 3-MCC deficiency and to encourage the development of evidence-based guidelines.

Infants with constitutional trisomy 21 are at increased risk of developing transient and acute megakaryoblastic leukemia (AMKL). Mutations in GATA1 have been identified in trisomy 21 patients with AMKL, and this lesion is thought to be an initial event by virtue of its presence during transient leukemia. Transient leukemia is also observed in phenotypically normal infants albeit much less commonly so. Almost all these infants are mosaic for trisomy 21, and the clinical course of transient leukemia recapitulates that observed in constitutional trisomy 21. We report a phenotypically normal infant with tetrasomy 21 transient leukemia, GATA1 mutation within exon 2, and trisomy 21 mosaicism restricted to the hematopoietic tissue. Two years after diagnosis, low levels of trisomy 21 persisted in the peripheral blood, which resolved 2.5 years after diagnosis. The GATA1 mutation was not detected at last follow-up. The literature review identified 32 phenotypically normal infants with transient leukemia. Ninety-one percent (29 of 32) were observed and three received chemotherapy at diagnosis of transient leukemia. Nineteen percent (6 of 32) developed acute leukemia, and four continued in remission (two died). Transient leukemia in trisomy 21 mosaicism recapitulates the condition observed in constitutional trisomy 21 at the biological and clinical levels. Infants should be followed for the development of acute leukemia.

Background: Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked methyl CpG binding protein 2 ( MeCP2 ) gene. Methods: One hundred sixteen patients with classical and atypical RTT were studied for mutations of the MeCP2 gene by using DHPLC and direct sequencing. Results: Causative mutations in the MeCP2 gene were identified in 63% of patients, representing a total of 30 different mutations. Mutations were identified in 72% of patients with classical RTT and one third of atypical cases studied (8 of 25). The authors found 17 novel mutations, including a complex gene rearrangement found in one individual involving two deletions and a duplication. The duplication was identical to a region within the 3′ untranslated region (UTR), and represents the first report of involvement of the 3′ UTR in RTT. The authors also report the identification of MeCP2 mutations in two males; a Klinefelter’s male with classic RTT (T158M) and a hemizygous male infant with a Xq27-28 inversion and a novel 32 bp frameshift deletion [1154(del32)]. Studies examining the relationship between mutation type, X-inactivation status, and severity of clinical presentation found significant differences in clinical presentation between different types of mutations. Mutations in the amino-terminus were significantly correlated with a more severe clinical presentation compared with mutations closer to the carboxyl-terminus of MeCP2. Skewed X-inactivation patterns were found in two asymptomatic carriers of MeCP2 mutations and six girls diagnosed with either atypical or classical RTT. Conclusion: This patient series confirms the high frequency of MeCP2 gene mutations causative of RTT in females and provides data concerning the molecular basis for clinical variability (mutation type and position and X-inactivation patterns).

A child with maple syrup urine disease type 2 (MSUD2) was found to be homozygous for a 10-bp MSUD2-gene deletion on chromosome 1. Both purported parents were tested, and neither carries the gene deletion. Polymorphic simple-sequence repeat analyses at 15 loci on chromosome 1 and at 16 loci on other chromosomes confirmed parentage and revealed that a de novo mutation prior to maternal meiosis I, followed by nondisjunction in maternal meiosis II, resulted in an oocyte with two copies of the de novo mutant allele. Fertilization by a sperm that did not carry a paternal chromosome 1 or subsequent mitotic loss of the paternal chromosome 1 resulted in the propositus inheriting two mutant MSUD2 alleles on two maternal number 1 chromosomes.

SummaryPatients with multiple schwannomas without vestibular schwannomas have been postulated to compose a distinct subclass of neurofibromatosis (NF), termed “schwannomatosis.” To compare the molecular-genetic basis of schwannomatosis with NF2, we examined the NF2 locus in 20 unrelated schwannomatosis patients and their affected relatives. Tumors from these patients frequently harbored typical truncating mutations of the NF2 gene and loss of heterozygosity of the surrounding region of chromosome 22. Surprisingly, unlike patients with NF2, no heterozygous NF2-gene changes were seen in normal tissues. Examination of multiple tumors from the same patient revealed that some schwannomatosis patients are somatic mosaics for NF2-gene changes. By contrast, other individuals, particularly those with a positive family history, appear to have an inherited predisposition to formation of tumors that carry somatic alterations of the NF2 gene. Further work is needed to define the pathogenetics of this unusual disease mechanism.

Schwannomas are benign nerve sheath tumors that most commonly occur singularly in otherwise normal individuals. Multiple schwannomas in a single patient are most often seen in neurofibromatosis 2 (NF2), but several recent reports suggest that schwannomatosis may also be a distinct clinical entity. We studied the clinical, radiographic, and pathologic features of 14 patients with multiple schwannomas who did not have vestibular schwannoma diagnostic of NF2. Most patients had peripheral nerve tumors that presented with pain. Many also had spinal nerve root and cranial nerve tumors. Three had multiple tumors limited to a single limb. We found that these 14 individuals did not exhibit phenotypic overlap with the neurofibromatoses. Only 1 of 14 patients had a positive family history. We conclude that patients with multiple schwannomas, who do not have vestibular schwannoma, comprise a distinct clinical problem, but further molecular genetic analysis is needed to define the pathophysiology of this disorder.

Three newborn infants of mothers with insulin dependent diabetes mellitus (IDDMm) were found to have multiple congenital malformations consisting of 3 or more VATER ascertainment anomalies. In addition, each of the 3 infants also had left lateral abdominal wall hernias, not previously noted in VATER or IDDMm infants. The hernias had intact overlying skin, were easily reducible and approximately 5-8 cm in diameter. Abdominal wall hernias with intact overlying skin are unusual, especially on the left side. One infant came to autopsy and was found to have hypoplasia (amyoplasia) of the abdominal wall musculature. Each of these 3 infants also had bilateral toe pre-axial polydactyly which has been rarely reported in VATER or in IDDMm infants. While there is overlap in the anomalies of VATER Association and infants of IDDMm, these 3 infants of IDDMm suggest that the phenotypes are distinct with separate etiologies. In VATER, an early insult to the allantois and subsequent vascular consequences have been etiologically implicated. The pre-axial toe potydactyly and abdominal wall hypoplasias are related to mesenchyme. The presence of macrosomia and increase in number of cells with IDDM can result in excess mesenchyme at the time of limb bud development which has been linked to polydactyly. The focal abdominal wall amyoplasia derives from myotomal mesoderm which migrates from 3 directions to fuse in the midline. An excess of mesodermal cells can cause imperfect fusion and migration resulting in a focal defect.

RCDP was initially diagnosed in a newborn female who had typical symmetric rhizomelic shortening of the extremities, metaphyseal changes, multiple punctate skeletal calcifications, icthyosis, bilateral cataracts and Koala bear facies. The patient succumbed at 12 weeks of age. Diagnostic evaluations were unrevealing, including normal peroxisomal very long chain fatty acids, phytanic acid hydrolase and plasmalogen biosynthesis. Fibroblasts where reanalyzed for defects in 3-beta-hydroxysteroid-Δ(8), Δ(7)-isomerase, which was recently identified to cause X-linked Conradi-Hunermann Syndrome. GC/MS analysis revealed a pattern of metabolites consistent with this enzymatic defect in cholesterol biosynthesis, specifically showing increased levels of 8-dehydrocholesterol and 8(9)-cholesterol. Genomic DNA was isolated from the patient's fibroblasts and the gene for 3-beta-hydroxysteroid-Δ(8), Δ(7)-isomerase (EBP, located at Xpll.2) was sequenced (all exons and intronic junctions). Results showed 3 mutations in cis in exon 2 : L42X (125T>A), W47X (140G>A) and L49L (147G>A)(a synonymous change). The other allele showed a wild type sequence. The EBP gene were sequenced in blood lymphocytes from both parents and were normal. This case highlights the heterogeneity of CDPX2. The range of phenotypic severity seen in this disorder is presumably due to variable lyonization. We show that severe CDPX2 is a phenocopy of peroxisomal RCDP. We have also identified a novel mutation that could have originated from a pseudogene or another unknown mechanism.

Background By late 1993, the genes for cystic fibrosis and Gaucher disease and the mutations common among Ashkenazi Jews had been identified. In response to these advances, heterozygote screening for cystic fibrosis and Gaucher disease was added to the more than 20-year-old Tay-Sachs disease screening program at New York University Medical Center, New York, NY. Objective To review the outcomes from the first 1000 patients screened through this program. Methods Patients and their referring physicians were informed about the new carrier tests. At the time of screening, patients could choose their tests (hexosaminidase A by enzyme analysis for Tay-Sachs disease or mutation analysis for cystic fibrosis and Gaucher disease). All partners of Tay-Sachs and cystic fibrosis carriers were tested. Prenatal diagnosis was offered and performed for carrier couples or mixed-marriage couples in whom the Ashkenazi Jewish partner was a carrier of Gaucher disease. Outcomes were measured by: (1) choice of tests, (2) decisions regarding prenatal diagnosis, and (3) phenotypes of children born to patients who underwent screening. Results The majority of Ashkenazi Jewish patients chose to have testing for all 3 diseases. If they previously underwent screening for Tay-Sachs disease, then they chose to undergo testing for cystic fibrosis and Gaucher disease. All carrier couples for each of these diseases went on to have prenatal testing. All mixed-marriage couples in whom the Jewish partner was found to be a carrier for Gaucher disease chose to have prenatal diagnosis. One fetus was identified as having cystic fibrosis. Since the program was initiated, no Ashkenazi Jewish baby has been born with any of these diseases at New York University Medical Center. Conclusions New tests can be readily incorporated into established heterozygote screening programs. The Ashkenazi Jewish population described herein tends to choose testing for all conditions for which heterozygote screening is available.