Acute Strokelike Presentation and Long-term Evolution of Diffusion Restriction Pattern in Ethylmalonic Encephalopathy.

Ethylmalonic encephalopathy is a rare autosomal recessive mitochondrial disorder caused by pathogenic biallelic variants in the ETHE1 gene. The phenotype of this disease has been attributed to deficiency in the mitochondrial sulfur dioxygenase leading to many downstream effects. Ethylmalonic encephalopathy classically presents with developmental regression, petechiae, acrocyanosis, and chronic diarrhea. The neurologic phenotype includes hypotonia, spastic diplegia, ataxia, and developmental delay. As more patients with this condition are described, the neurologic phenotype continues to expand. Although strokelike episodes or metabolic strokes have been studied in other mitochondrial disorders, they have not been thoroughly reported in this disorder. Herein, we describe 3 patients with ethylmalonic encephalopathy who presented clinically with strokelike episodes and strokelike abnormalities on brain magnetic resonance imaging in the setting of acute illness, and the long-term sequelae with evolution into cystic changes in one of these subjects.

Newborn Screening for Inherited Metabolic Disorders: Early Identification and Long-Term Care for Patients in the Plain Community, Wisconsin, 2011-2017.

The Plain community is the fastest-growing religious minority in Wisconsin. This community has a high incidence of genetic disorders, many of which are identifiable through newborn screening. We describe efforts by the Wisconsin Newborn Screening Program (WNSP) to improve health care in the Plain community by targeting early identification of, and intervention for, patients with inherited metabolic disorders. WNSP formed partnerships with families and health care providers to increase awareness of screening procedures and the intended benefits of screening, modify testing algorithms to enhance detection, and establish medical homes for patients with confirmed disorders. The estimated number of Plain newborns screened increased by 25.5% during the study period, from 547 in 2011 to 736 in 2017; 122 persons underwent carrier testing, and 143 newborns received second-tier testing. From 2014 to 2017, affected patients received 71 metabolic evaluations in their community medical home without travel to major health centers. This article demonstrates how a comprehensive public health program can help increase screening rates, enhance detection, and establish follow-up care in a hard-to-reach religious community. A key lesson learned was the importance of communication among all stakeholders to develop an effective public health program.

Familial segregation of a 5q15-q21.2 deletion associated with facial dysmorphism and speech delay.

We report a two-generation family with four females harboring an 8.5Mb heterozygous deletion of 5q15-q21.2 who present with dysmorphic craniofacial features and speech delay. We hypothesize haploinsufficiency of CHD1 to be contributing to the clinical features observed in this family.

Improved clinical outcome following liver transplant in patients with ethylmalonic encephalopathy.

Ethylmalonic encephalopathy (EE) is a rapidly progressive autosomal recessive mitochondrial disease caused by biallelic pathogenic variants in the ETHE1 gene that encodes the mitochondrial sulfur dioxygenase. It is characterized by neurodevelopmental delay and regression, pyramidal and extrapyramidal signs, recurrent petechiae, chronic diarrhea, and orthostatic acrocyanosis. Laboratory findings include elevated serum levels of lactate and C4-C5 acylcarnitines, and elevated urinary excretion of ethylmalonic acid and C4-C6 acylglycines, notably isobutyrylglycine and 2-methylbutyrylglycine. These findings are attributed to deficiency of the mitochondrial sulfur dioxygenase resulting in toxic accumulation of hydrogen sulfide metabolites in vascular endothelium and mucosal cells of the large intestine. Medical management has thus far been directed toward decreasing the accumulation of hydrogen sulfide metabolites using a combination of metronidazole and N-acetylcysteine. More recently, orthotopic liver transplant (OLT) has been reported as a new therapeutic option for EE. Here, we report two additional cases of EE who achieved psychomotor developmental improvement after 7- and 22-months following OLT. The second case serves as the longest developmental outcome follow-up reported, thus far, following OLT for EE. This report provides additional evidence to validate OLT as a promising therapeutic approach for what was considered to be a fatal disease.

Volatile anesthesia for a pediatric patient with very long-chain acyl-coenzyme A dehydrogenase deficiency: A case report.

We report the case of a 3-year-old boy with very long-chain acyl-coenzyme A dehydrogenase deficiency presenting for adenotonsillectomy who was successfully and safely managed with a balanced anesthetic including sevoflurane. The anesthetic management is described, and the controversy surrounding volatile anesthetics in these patients is discussed.

Prenatal presentation of Mabry syndrome with congenital diaphragmatic hernia and phenotypic overlap with Fryns syndrome.

We report on a family in which initial features were compatible with Fryns syndrome. The first sibling was a stillborn female with a left diaphragmatic hernia (DH). Her clinical features overlapped with Fryns syndrome. The second pregnancy, a male fetus, was followed for polyhydramnios, hypoplastic mandible, mild enlargement of the fetal bladder, hydronephrosis, and rocker bottom foot deformities. He had facial features similar to his sibling and a large cleft of the secondary palate, small jaw, and secundum atrial septal defect. He underwent surgical repair of imperforate anus, intestinal malrotation, and placement of mucous fistula for biopsy positive Hirschsprung disease. An elevated alkaline phosphatase level of 1569 U/L was reported. Whole exome sequencing performed on the second child demonstrated compound heterozygosity for the PIGV gene with the p.A341E and p.A418D variants in trans. Hyperphosphatasia with mental retardation syndrome (HPMRS) is caused by mutations in PIGV and includes hyperphosphatasia as a diagnostic hallmark. Our patient exhibited hyperphosphatasia but without any storage material in his skin cells. His features remain similar to his sister's, but includes seizures and lacks diaphragmatic hernia. Until now, HPMRS and Fryns syndrome, despite overlapping features, were considered mutually exclusive as HPMRS involves hyperphosphatasia and Fryns typically exhibits DH. Recent identification of PIGN mutations associated with several cases of Fryns syndrome point to a common pathogenetic etiology involving inborn errors of the glycosylphosphatidylinositiol anchor biosynthetic pathway. A diagnosis of HPMRS should be considered when DH is encountered on prenatal ultrasound.

Identification and functional analysis of an ADAMTSL1 variant associated with a complex phenotype including congenital glaucoma, craniofacial, and other systemic features in a three-generation human pedigree.

Developmental glaucoma can occur as an isolated or syndromic condition and is genetically heterogeneous. We describe a three-generation family affected with developmental glaucoma, myopia, and/or retinal defects associated with variable craniofacial/dental, auditory, brain, renal, and limb anomalies. Whole-exome sequencing identified a heterozygous c.124T> C, p.(Trp42Arg) allele in ADAMTSL1; cosegregation analysis confirmed the presence of this allele in four affected family members. The mutation affects a highly conserved residue and is strongly predicted to have a deleterious effect on protein function. Trp42 is normally modified by protein C-mannosylation, an unusual post-translational modification. Comparison of ADAMTSL1-WT (also known as punctin-1) and ADAMTSL1-p.Trp42Arg in vitro demonstrated that the latter was not secreted from transfected cells but retained intracellularly. Moreover, ADAMTSL1-p.Trp42Arg reduced secretion of cotransfected wild-type ADAMTSL1, suggesting a dominant negative effect for this mutation. These data imply a multisystem role for ADAMTSL1 and present the first disease-associated variant affecting a C-mannosylation motif.

Biallelic Mutations in MITF Cause Coloboma, Osteopetrosis, Microphthalmia, Macrocephaly, Albinism, and Deafness.

Human MITF is, by convention, called the "microphthalmia-associated transcription factor" because of previously published seminal mouse genetic studies; however, mutations in MITF have never been associated with microphthalmia in humans. Here, we describe a syndrome that we term COMMAD, characterized by coloboma, osteopetrosis, microphthalmia, macrocephaly, albinism, and deafness. COMMAD is associated with biallelic MITF mutant alleles and hence suggests a role for MITF in regulating processes such as optic-fissure closure and bone development or homeostasis, which go beyond what is usually seen in individuals carrying monoallelic MITF mutations.

Glycomacropeptide for nutritional management of phenylketonuria: a randomized, controlled, crossover trial.

BACKGROUND: To prevent cognitive impairment, phenylketonuria requires lifelong management of blood phenylalanine (Phe) concentration with a low-Phe diet. The diet restricts intake of Phe from natural proteins in combination with traditional amino acid medical foods (AA-MFs) or glycomacropeptide medical foods (GMP-MFs) that contain primarily intact protein and a small amount of Phe. OBJECTIVE: We investigated the efficacy and safety of a low-Phe diet combined with GMP-MFs or AA-MFs providing the same quantity of protein equivalents in free-living subjects with phenylketonuria. DESIGN: This 2-stage, randomized crossover trial included 30 early-treated phenylketonuria subjects (aged 15-49 y), 20 with classical and 10 with variant phenylketonuria. Subjects consumed, in random order for 3 wk each, their usual low-Phe diet combined with AA-MFs or GMP-MFs. The treatments were separated by a 3-wk washout with AA-MFs. Fasting plasma amino acid profiles, blood Phe concentrations, food records, and neuropsychological tests were obtained. RESULTS: The frequency of medical food intake was higher with GMP-MFs than with AA-MFs. Subjects rated GMP-MFs as more acceptable than AA-MFs and noted improved gastrointestinal symptoms and less hunger with GMP-MFs. ANCOVA indicated no significant mean ± SE increase in plasma Phe (62 ± 40 µmol/L, P = 0.136), despite a significant increase in Phe intake from GMP-MFs (88 ± 6 mg Phe/d, P = 0.026). AA-MFs decreased plasma Phe (-85 ± 40 µmol/L, P = 0.044) with stable Phe intake. Blood concentrations of Phe across time were not significantly different (AA-MFs = 444 ± 34 µmol/L, GMP-MFs = 497 ± 34 µmol/L), suggesting similar Phe control. Results of the Behavior Rating Inventory of Executive Function were not significantly different. CONCLUSIONS: GMP-MFs provide a safe and acceptable option for the nutritional management of phenylketonuria. The greater acceptability and fewer side effects noted with GMP-MFs than with AA-MFs may enhance dietary adherence for individuals with phenylketonuria. This trial was registered at www.clinicaltrials.gov as NCT01428258.

TBC1D24 genotype-phenotype correlation: Epilepsies and other neurologic features.

OBJECTIVE: To evaluate the phenotypic spectrum associated with mutations in TBC1D24. METHODS: We acquired new clinical, EEG, and neuroimaging data of 11 previously unreported and 37 published patients. TBC1D24 mutations, identified through various sequencing methods, can be found online (http://lovd.nl/TBC1D24). RESULTS: Forty-eight patients were included (28 men, 20 women, average age 21 years) from 30 independent families. Eighteen patients (38%) had myoclonic epilepsies. The other patients carried diagnoses of focal (25%), multifocal (2%), generalized (4%), and unclassified epilepsy (6%), and early-onset epileptic encephalopathy (25%). Most patients had drug-resistant epilepsy. We detail EEG, neuroimaging, developmental, and cognitive features, treatment responsiveness, and physical examination. In silico evaluation revealed 7 different highly conserved motifs, with the most common pathogenic mutation located in the first. Neuronal outgrowth assays showed that some TBC1D24 mutations, associated with the most severe TBC1D24-associated disorders, are not necessarily the most disruptive to this gene function. CONCLUSIONS: TBC1D24-related epilepsy syndromes show marked phenotypic pleiotropy, with multisystem involvement and severity spectrum ranging from isolated deafness (not studied here), benign myoclonic epilepsy restricted to childhood with complete seizure control and normal intellect, to early-onset epileptic encephalopathy with severe developmental delay and early death. There is no distinct correlation with mutation type or location yet, but patterns are emerging. Given the phenotypic breadth observed, TBC1D24 mutation screening is indicated in a wide variety of epilepsies. A TBC1D24 consortium was formed to develop further research on this gene and its associated phenotypes.

Clinical relevance of the discrepancy in phenylalanine concentrations analyzed using tandem mass spectrometry compared with ion-exchange chromatography in phenylketonuria.

INTRODUCTION: Metabolic control of phenylketonuria (PKU) and compliance with the low-phenylalanine (phe) diet are frequently assessed by measuring blood phe concentrations in dried blood spots (DBS) collected by patients instead of plasma phe concentrations. OBJECTIVE: Our objective was to investigate the difference in blood phe concentrations in DBS collected by subjects and analyzed using either a validated newborn screening tandem mass spectrometry (MS/MS) protocol or ion-exchange chromatography (IEC) compared to plasma phe concentrations obtained simultaneously and analyzed using IEC. DESIGN: Three to four fasting blood samples were obtained from 29 subjects with PKU, ages 15-49 years. Capillary blood was spotted on filter paper by each subject and the DBS analyzed using both MS/MS and IEC. Plasma was isolated from venous blood and analyzed using IEC. RESULTS: Blood phe concentrations in DBS analyzed using MS/MS are 28% ± 1% (n = 110, p < 0.0001) lower than plasma phe concentrations analyzed using IEC resulting in a blood phe concentration of 514 ± 23 µmol/L and a plasma phe concentration of 731 ± 32 µmol/L (mean ± SEM). This discrepancy is larger when plasma phe is > 600 µmol/L. Due to the large variability across subjects of 13.2%, a calibration factor to adjust blood phe concentrations is not recommended. Analysis of DBS using IEC reduced the discrepancy to 15 ± 2% lower phe concentrations compared to plasma analyzed using IEC (n = 38, p = 0.0001). This suggests that a major contributor to the discrepancy in phe concentrations is the analytical method. CONCLUSION: Use of DBS analyzed using MS/MS to monitor blood phe concentrations in individuals with PKU yields significantly lower phe levels compared to plasma phe levels analyzed using IEC. Optimization of current testing methodologies for measuring phe in DBS, along with patient education regarding the appropriate technique for spotting blood on filter paper is needed to improve the accuracy of using DBS to measure phe concentrations in PKU management.

Inborn Errors of Metabolism (Metabolic Disorders).

By their very nature, rare inborn errors of metabolism challenge the generation and application of evidence-based medicine. • On the basis of limited research evidence as well as consensus, newborn screening for select metabolic disorders, including phenylketonuria, medium-chain acyl CoA dehydrogenase deficiency, and glutaric acidemia type I, may improve long-term outcomes for affected children. • On the basis of primarily consensus, due to lack of relevant clinical studies, inborn errors due to defects in the metabolism of energy sources (protein, fatty acids, and carbohydrates) may present in infancy with overwhelming metabolic decompensation, and initial laboratory evaluations may reveal hyperammonemia, nonketotic hypoglycemia, or a metabolic acidosis with an elevated anion gap, depending on the disorder. • On the basis of primarily consensus, due to lack of relevant clinical studies, specific laboratory testing for inborn errors of metabolism should include plasma amino acids, urine organic acids, plasma carnitine, and plasma acylcarnitine profile. • On the basis of primarily consensus, due to lack of relevant clinical studies, disorders of cellular organelles, such as lysosomal and peroxisomal disorders, may present with progressive organomegaly, developmental regression, dysmorphic facial characteristics. or sensory loss.

Successful pregnancy and delivery in a woman with propionic acidemia from the Amish community.

Propionic acidemia (PA) is an inborn error of protein metabolism with a variable clinical presentation ranging from neonatal encephalopathy to seemingly asymptomatic individuals who present with cardiomyopathy or sudden death. PA is recognized in the Amish population, often with an early asymptomatic course and eventual cardiac complications. Thus, Amish women with PA may reach reproductive age without clinical sequelae, but are at increased risk for metabolic decompensation during pregnancy, delivery and postpartum period. We describe the care of an Amish woman with PA during her first pregnancy and delivery.

Single-dose, subcutaneous recombinant phenylalanine ammonia lyase conjugated with polyethylene glycol in adult patients with phenylketonuria: an open-label, multicentre, phase 1 dose-escalation trial.

BACKGROUND: Phenylketonuria is an inherited disease caused by impaired activity of phenylalanine hydroxylase, the enzyme that converts phenylalanine to tyrosine, leading to accumulation of phenylalanine and subsequent neurocognitive dysfunction. Phenylalanine ammonia lyase is a prokaryotic enzyme that converts phenylalanine to ammonia and trans-cinnamic acid. We aimed to assess the safety, tolerability, pharmacokinetic characteristics, and efficacy of recombinant Anabaena variabilis phenylalanine ammonia lyase (produced in Escherichia coli) conjugated with polyethylene glycol (rAvPAL-PEG) in reducing phenylalanine concentrations in adult patients with phenylketonuria. METHODS: In this open-label, phase 1, multicentre trial, single subcutaneous injections of rAvPAL-PEG were given in escalating doses (0·001, 0·003, 0·010, 0·030, and 0·100 mg/kg) to adults with phenylketonuria. Participants aged 18 years or older with blood phenylalanine concentrations of 600 µmol/L or higher were recruited from among patients attending metabolic disease clinics in the USA. The primary endpoints were safety and tolerability of rAvPAL-PEG. Secondary endpoints were the pharmacokinetic characteristics of the drug and its effect on concentrations of phenylalanine. Participants and investigators were not masked to assigned dose group. This study is registered with ClinicalTrials.gov, number NCT00925054. FINDINGS: 25 participants were recruited from seven centres between May 6, 2008, and April 15, 2009, with five participants assigned to each escalating dose group. All participants were included in the safety population. The most frequently reported adverse events were injection-site reactions and dizziness, which were self-limited and without sequelae. Two participants had serious adverse reactions to intramuscular medroxyprogesterone acetate, a drug that contains polyethylene glycol as an excipient. Three of five participants given the highest dose of rAvPAL-PEG (0·100 mg/kg) developed a generalised skin rash. By the end of the study, all participants had developed antibodies against polyethylene glycol, and some against phenylalanine ammonia lyase as well. Drug concentrations peaked about 89-106 h after administration of the highest dose. Treatment seemed to be effective at reducing blood phenylalanine in all five participants who received the highest dose (mean reduction of 54·2% from baseline), with a nadir about 6 days after injection and an inverse correlation between drug and phenylalanine concentrations in plasma. Phenylalanine returned to near-baseline concentrations about 21 days after the injection. INTERPRETATION: Subcutaneous administration of rAvPAL-PEG in a single dose of up to 0·100 mg/kg was fairly safe and well tolerated in adult patients with phenylketonuria. At the highest dose tested, rAvPAL-PEG reduced blood phenylalanine concentrations. In view of the development of antibodies against polyethylene glycol (and in some cases against phenylalanine ammonia lyase), future studies are needed to assess the effect of repeat dosing. FUNDING: BioMarin Pharmaceutical.

Phenotype of FOXP2 haploinsufficiency in a mother and son.

Disruptions in FOXP2, a transcription factor, are the only known monogenic cause of speech and language impairment. We report on clinical findings for two new individuals with a submicroscopic deletion of FOXP2: a boy with severe apraxia of speech and his currently moderately affected mother. A 1.57 Mb deletion on chromosome 7q31 was detected by array comparative genomic hybridization (aCGH). In addition to FOXP2, the patients' deletion involves two other genes, MDFIC and PPP1R3A, neither of which has been associated with speech or language disorders. Thus, findings for these two family members provide informative phenotypic information on FOXP2 haploinsufficiency. Evaluation by a clinical geneticist indicated no major congenital anomalies or dysmorphic features. Evaluations by a clinical psychologist and occupational therapist indicated cognitive-linguistic processing and sensorimotor control deficits, but did not support a diagnosis of autism spectrum disorder. Evaluation by clinical and research speech pathologists confirmed that both patients' speech deficits met contemporary criteria for apraxia of speech. Notably, the patients were not able to laugh, cough, or sneeze spontaneously, replicating findings reported for two other FOXP2 cases and a potential diagnostic sign of nonsyndromic apraxia of speech. Speech severity findings for the boy were not consistent with the hypothesis that loss of maternal FOXP2 should be relatively benign. Better understanding of the behavioral phenotype of FOXP2 disruptions will aid identification of patients, toward an eventual understanding of the pathophysiology of syndromic and nonsyndromic apraxia of speech.

A case of congenitally absent left internal carotid artery: vascular malformations in 22q11.2 deletion syndrome.

Our report is on a Hispanic boy for whom, shortly after birth, clinical suspicion of 22q11.2 deletion syndrome (22q11.2DS) was raised as a result of his characteristic features, including facial dysmorphisms and hypotonia. The 22q11.2DS was confirmed by fluorescence in situ hybridization (FISH), noting a 22q11.2 deletion. Further evaluation revealed complete congenital absence of the left internal carotid artery and focal pachygyria of the left hemisphere. Multiple cardiac and vascular anomalies have been previously described in 22q11 deletion syndrome, but congenital absence of the internal carotid has not been previously reported in the literature. We present a clinical case report in detail of this unique 22q11.2 deletion syndrome associated finding.