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CAD is a large, 2225 amino acid multienzymatic protein required for de novo pyrimidine biosynthesis. Pathological CAD variants cause a developmental and epileptic encephalopathy which is highly responsive to uridine supplements. CAD deficiency is difficult to diagnose because symptoms are nonspecific, there is no biomarker, and the protein has over 1000 known variants. To improve diagnosis, we assessed the pathogenicity of 20 unreported missense CAD variants using a growth complementation assay that identified 11 pathogenic variants in seven affected individuals; they would benefit from uridine treatment. We also tested nine variants previously reported as pathogenic and confirmed the damaging effect of seven. However, we reclassified two variants as likely benign based on our assay, which is consistent with their long-term follow-up with uridine. We found that several computational methods are unreliable predictors of pathogenic CAD variants, so we extended the functional assay results by studying the impact of pathogenic variants at the protein level. We focused on CAD's dihydroorotase (DHO) domain because it accumulates the largest density of damaging missense changes. The atomic-resolution structures of eight DHO pathogenic variants, combined with functional and molecular dynamics analyses, provided a comprehensive structural and functional understanding of the activity, stability, and oligomerization of CAD's DHO domain. Combining our functional and protein structural analysis can help refine clinical diagnostic workflow for CAD variants in the genomics era., (© 2023 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM.)

We present the rare case of lipomatous atrial septal hypertrophy associated with adrenocorticotropin hormone therapy in an infant with West syndrome, highlighting their relatively benign nature and good prognosis in children, and the relevance of the differential diagnosis with more dangerous cardiac masses in order to avoid aggressive diagnostic and therapeutic interventions.

Rationale: Mucopolysaccharidosis type VI (MPS VI) or Maroteaux-Lamy syndrome is produced by the deficiency of the enzyme arylsulfatase B, responsible for the hydrolysis of N-acetyl-D-galactosamine, chondroitin sulfate, and dermatan sulfate., Patient Concerns: A 3-year-old male with Moroccan origins is the index case. He had healthy consanguineous parents and 4 healthy brothers and sisters. The patient showed a wide spectrum of symptoms including skeletal dysplasia and short stature with elevated glycosaminoglycans (GAGs) in urine., Diagnoses, Interventions, and Outcomes: GAGs were quantified by spectrometry method with 1,9-dimethylen blue in 24-hour urine samples. The qualitative analysis of urine GAGs was obtained by thin-layer chromatography to determine the predominant presence of dermatan sulfate. The activities of both arylsulfatase B and beta-galactosidase as well as genetic studies were performed in dried blood spots. The genetic study was performed with deoxyribonucleic acid by massive sequencing a of lisosomal storage diseases. Results showed a new mutation c.263A > C with the severe phenotype in homozygous in the patient. The familiar study of ARSB and GLB1 genes presented some asymptomatic SNPs but with a discrete decrease in the activity of arylsulfatase B and beta-galactosidase. After an early detection by pediatricians, and both enzymatic and genetic confirmation, the patient had a good response to substitutive enzymatic treatment with galsulfase., Lessons: Mucoplysaccharidosis type VI is an autosomal recessive rare disease characterized by a lysosomal storage disorder. Although a number of mutations have been already associated to the disease, we have found a new mutation located in the arylsulfatase B enzyme gene. We have described that this mutation is the ultimate cause of a severe presentation of the disease.

Unlabelled: Mutations in the L1CAM gene have been identified in the following various X-linked neurological disorders: congenital hydrocephalus; mental retardation, aphasia, shuffling gait, and adducted thumbs (MASA) syndrome; spastic paraplegia; and agenesis of the corpus callosum. These conditions are currently considered different phenotypes of a single entity known as L1 syndrome. We present three families with L1 syndrome. Sequencing of the L1CAM gene allowed the identification of the following mutations involved: a known splicing mutation (c.3531-12G>A) and two novel ones: a missense mutation (c.1754A>C; p.Asp585Ala) and a nonsense mutation (c.3478C>T; p.Gln1160Stop). The number of affected males and carrier females identified in a relatively small population suggests that L1 syndrome may be under-diagnosed., Conclusion: L1 syndrome should be considered in the differential diagnosis of intellectual disability or mental retardation in children, especially when other signs such as hydrocephalus or adducted thumbs are present.

Introduction: Pompe disease is a generalized progressive disease caused by a deficiency of the lysosome enzyme acid alpha-glucosidase (GAA). We present three cases with different clinical symptomatology and treated with enzyme replacement therapy (ERT) with positive evolution., Case Reports: Case 1: three-month old male, with weakness and rejecting meals; mild hepatomegaly, discrete macroglossia and muscular hypotony; and increased muscular enzymes. Case 2: five-month old male, with delayed motor development, severe neurosensory deafness, and respiratory disorder of difficult evolution; muscular hypotony; and mild increase in creatine kinase. Case 3: 22-year old male, with progressive dyspnea, with history of increased creatine kinase and transaminases, and hypercholesterolemia. He suffered from severe respiratory failure requiring endotraqueal intubation Muscular biopsy showed glycogen storage suggestive of Pompe disease. In the three cases, the EMG showed a characteristic pattern with pseudomyotonic discharges and the deficiency in GAA was confirmed in lymphocytes. One single mutation was observed in one case and two in the other two cases. Every patient received ERT showing a favorable evolution; with disappearance of cardiac disorders in case 1, improvement in motor development in both infants and no longer need for mechanical ventilation in case 3., Conclusion: Pompe disease has a wide variability in clinical expression. ERT achieves a good response, especially in infant forms of the disease. The survival of treated patients with these Pompe disease forms will allow knowing further the course of the disease.

Background: Infant botulism (IB) is caused by the intestinal colonization by Clostridium botulinum in the first year of life and its subsequent production of neurotoxins. Traditionally, IB has been associated to honey consumption. IB cases tend to cluster in geographic regions. In Europe, IB is a rare disorder. From 1976 through 2006, 65 cases were identified in 13 European countries. In Spain, in the last 15 years, most of the cases have been reported in one region, Andalusia (Southern Spain). A specific treatment for IB type A and type B (BabyBIG) is available outside of the United States since 2005., Methods: and aims: We performed a retrospective review of IB cases detected in Andalusia since 1997 and compare them with the cases of IB reported in Europe., Results: We identified 11 confirmed cases of IB in Andalusia since 1997, and 14 cases in Spain. Nine out of 11 cases were detected since 2007; none of these infants had been exposed to honey consumption. One case in 1997 and another in 2000 were associated to honey. Two cases were treated with BabyBIG in 2007. In the period 2006-2012 the cases of IB reported in Europe were 54., Conclusions: We identified a considerable increase in the incidence of IB since 2006. A tendency to a reduction in the number of cases of IB linked to honey consumption has also been identified. An increase in the exposure to these bacteria from the environment could be presumed. Clinicians should maintain a high index of suspicion for this treatable disorder., (Copyright © 2014 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

Introduction: Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is a rare condition that has only recently been reported. Here we present two new cases belonging to the same family., Case Reports: Case 1: 17-month-old boy with severe underdevelopment in all areas, absence of language and eye contact. The examination revealed microcephaly with spastic tetraparesis. A magnetic resonance imaging scan showed predominantly vermian atrophy of the cerebellum with loss of volume of both nuclei of the putamen and the head of the caudate, and a pattern of hypomyelination of the white matter. Electromyography recording highlighted the presence of a predominantly motor pattern of chronic polyneuropathy. Homovallinic acid and 5-hydroxyindoleacetic acid values were lower than usual. Treatment with levodopa/carbidopa was not effective. Case 2: 11-month-old girl, the sister of the boy in the previous case. The patient presented severe underdevelopment in all areas and microcephaly with spastic tetraparesis was detected in the clinical examination. Magnetic resonance imaging of the head showed findings that could be superimposed upon those of the brother, with hypomyelination, cerebellar atrophy and involvement of the putamen and both caudates; electromyography findings were consistent with motor polyneuropathy of a demyelinating nature. Homovallinic acid and 5-hydroxyindoleacetic acid values in cerebrospinal fluid were lower than usual. Treatment with levodopa/carbidopa was ineffective., Conclusions: These two new cases help characterise this condition better and reinforce the hypothesis of the genetic origin of the syndrome, given that the two cases occurred in the same family.

Before 2006, Pompe disease or glycogenosis storage disease type II was an incurable disease whose treatment was merely palliative. The development of a recombinant human alpha-glucosidase enzymatic replacement therapy has become the first specific treatment for this illness. The aim of this guide is to serve as reference for the management of the late-onset Pompe disease, the type of Pompe disease that develops after one year of age. In the guide a group of Spanish experts make specific recommendations about diagnosis, follow-up and treatment of this illness. With regard to diagnosis, the dried blood spots method is essential as the first step for the diagnosis of Pompe disease. The confirmation of the diagnosis of Pompe disease must be made by means of an study of enzymatic activity in isolated lymphocytes or a mutation analysis of the alpha-glucosidase gene. With regard to treatment with enzymatic replacement therapy, the experts say that is effective improving or stabilizating the motor function and the respiratory function and it must be introduced when the first symptoms attributable to Pompe disease appear.