Autophagy regulates the degradation of damaged organelles and protein aggregates, and is critical for neuronal development, homeostasis, and maintenance, yet few neurodevelopmental disorders have been associated with pathogenic variants in genes encoding autophagy-related proteins. We report three individuals from two unrelated families with a neurodevelopmental disorder characterized by speech and motor impairment, and similar facial characteristics. Rare, conserved, bi-allelic variants were identified in ATG4D, encoding one of four ATG4 cysteine proteases important for autophagosome biogenesis, a hallmark of autophagy.
View Article and Find Full Text PDFVacuolar-type H+-ATPase (V-ATPase) is a multimeric complex present in a variety of cellular membranes that acts as an ATP-dependent proton pump and plays a key role in pH homeostasis and intracellular signalling pathways. In humans, 22 autosomal genes encode for a redundant set of subunits allowing the composition of diverse V-ATPase complexes with specific properties and expression. Sixteen subunits have been linked to human disease.
View Article and Find Full Text PDFPurpose: 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).
SMARCA4 encodes a central ATPase subunit in the BRG1-/BRM-associated factors (BAF) or polybromo-associated BAF (PBAF) complex in humans, which is responsible in part for chromatin remodeling and transcriptional regulation. Variants in this and other genes encoding BAF/PBAF complexes have been implicated in Coffin-Siris Syndrome, a multiple congenital anomaly syndrome classically characterized by learning and developmental differences, coarse facial features, hypertrichosis, and underdevelopment of the fifth digits/nails of the hands and feet. Individuals with SMARCA4 variants have been previously reported and appear to display a variable phenotype.
View Article and Find Full Text PDFAdams-Oliver syndrome (AOS) is a congenital condition characterized by aplasia cutis congenita of the scalp and transverse limb defects. Other clinical features reported in association with AOS include cardiac malformations, cutis marmorata telangiectatica congenita, prenatal complications, and ophthalmic abnormalities. Reported ophthalmic manifestations range from Peters anomaly-like findings and cataract formation to incomplete or abnormal retinal vasculature, optic nerve hypoplasia, and rod dystrophy.
View Article and Find Full Text PDFSATB2-associated syndrome (SAS) is an autosomal dominant neurodevelopmental disorder caused by alterations in the SATB2 gene. Here we present a review of published pathogenic variants in the SATB2 gene to date and report 38 novel alterations found in 57 additional previously unreported individuals. Overall, we present a compilation of 120 unique variants identified in 155 unrelated families ranging from single nucleotide coding variants to genomic rearrangements distributed throughout the entire coding region of SATB2.
View Article and Find Full Text PDFPrevious reports have identified SLC6A1 variants in patients with generalized epilepsies, such as myoclonic-atonic epilepsy and childhood absence epilepsy. However, to date, none of the identified SLC6A1 variants has been functionally tested for an effect on GAT-1 transporter activity. The purpose of this study was to determine the incidence of SLC6A1 variants in 460 unselected epilepsy patients and to evaluate the impact of the identified variants on γ-aminobutyric acid (GABA)transport.
View Article and Find Full Text PDFMitochondrial DNA maintenance (mtDNA) defects have a wide range of causes, each with a set of phenotypes that overlap with many other neurological or muscular diseases. Clinicians face the challenge of narrowing down a long list of differential diagnosis when encountered with non-specific neuromuscular symptoms. Biallelic pathogenic variants in the Thymidine Kinase 2 (TK2) gene cause a myopathic form of mitochondrial DNA maintenance defect.
View Article and Find Full Text PDFObjective: To delineate the developmental and progressive neurodegenerative features in 9 young adults with the atypical form of Chediak-Higashi disease (CHD) enrolled in a natural history study.
Methods: Patients with atypical clinical features, but diagnostically confirmed CHD by standard evaluation of blood smears and molecular genotyping, underwent complete neurologic evaluation, MRI of the brain, electrophysiologic examination, and neuropsychological testing. Fibroblasts were collected to investigate the cellular phenotype and correlation with the clinical presentation.
SYNJ1 encodes a polyphosphoinositide phosphatase, synaptojanin 1, which contains two consecutive phosphatase domains and plays a prominent role in synaptic vesicle dynamics. Autosomal recessive inherited variants in SYNJ1 have previously been associated with two different neurological diseases: a recurrent homozygous missense variant (p.Arg258Gln) that abolishes Sac1 phosphatase activity was identified in three independent families with early onset parkinsonism, whereas a homozygous nonsense variant (p.
View Article and Find Full Text PDFObjective: To determine the phenotypic spectrum caused by mutations in GRIN1 encoding the NMDA receptor subunit GluN1 and to investigate their underlying functional pathophysiology.
Methods: We collected molecular and clinical data from several diagnostic and research cohorts. Functional consequences of GRIN1 mutations were investigated in Xenopus laevis oocytes.
Objective: To delineate the developmental and progressive neurodegenerative features in 9 young adults with the atypical form of Chediak-Higashi disease (CHD) enrolled in a natural history study.
Methods: Patients with atypical clinical features, but diagnostically confirmed CHD by standard evaluation of blood smears and molecular genotyping, underwent complete neurologic evaluation, MRI of the brain, electrophysiologic examination, and neuropsychological testing. Fibroblasts were collected to investigate the cellular phenotype and correlation with the clinical presentation.
Noonan syndrome is a common genetic disorder that causes multiple congenital abnormalities and a large number of potential health conditions. Most affected individuals have characteristic facial features that evolve with age; a broad, webbed neck; increased bleeding tendency; and a high incidence of congenital heart disease, failure to thrive, short stature, feeding difficulties, sternal deformity, renal malformation, pubertal delay, cryptorchidism, developmental or behavioral problems, vision problems, hearing loss, and lymphedema. Familial recurrence is consistent with an autosomal dominant mode of inheritance, but most cases are due to de novo mutations.
View Article and Find Full Text PDFBackground: Mutations in LYST, a gene encoding a putative lysosomal trafficking protein, cause Chédiak-Higashi syndrome (CHS), an autosomal recessive disorder typically characterized by infantile-onset hemophagocytic syndrome and immunodeficiency, and oculocutaneous albinism. A small number of reports of rare, attenuated forms of CHS exist, with affected individuals exhibiting progressive neurodegenerative disease beginning in early adulthood with cognitive decline, parkinsonism, features of spinocerebellar degeneration, and peripheral neuropathy, as well as subtle pigmentary abnormalities and subclinical or absent immune dysfunction.
Methods: In a consanguineous Pakistani kindred with clinical phenotypes consistent with attenuated CHS, we performed SNP array-based homozygosity mapping and whole gene sequencing of LYST.
We investigated an outbreak of Coxsackie B4 arthritis in a neonatal unit involving 20 neonates and 12 staff members, over an eight-month period. Laboratory investigations, serology tests, indicate that the outbreak was caused by Coxsackie B4 virus. Contamination of one of the overhead water reservoirs, supplying the nursery, was responsible.
View Article and Find Full Text PDFBackground: The hard edges of adult finger clip probes of the pulse oximetry oxygen saturation (POOS) monitor can cause skin damage if used for prolonged periods in a neonate. Covering the skin under the probe with Micropore surgical tape or a gauze piece might prevent such injury. The study was done to see if the protective covering would affect the accuracy of the readings.
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