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1.
Greig Cephalopolysyndactyly Contiguous Gene Syndrome: Case Report and Literature Review.
Kozma, K, Bembea, M, Jurca, CM, Ioana, M, Streață, I, Şoşoi, SŞ, Pirvu, A, Petchesi, CD, Szilágyi, A, Sava, CN, et al
Genes. 2021;(11)
Abstract
Greig cephalopolysyndactyly syndrome (GCPS) is a rare genetic disorder (about 200 cases reported), characterized by macrocephaly, hypertelorism, and polysyndactyly. Most of the reported GCPS cases are the results of heterozygous loss of function mutations affecting the GLI3 gene (OMIM# 175700), while a small proportion of cases arise from large deletions on chromosome 7p14 encompassing the GLI3 gene. To our knowledge, only 6 patients have been reported to have a deletion with an exact size (given by genomic coordinates) and a gene content larger than 1 Mb involving the GLI3 gene. This report presents a patient with Greig cephalopolysyndactyly contiguous gene syndrome (GCP-CGS) diagnosed with a large, 18 Mb deletion on chromosome 7p14.2-p11.2. Similar cases are reviewed in the literature for a more accurate comparison between genotype and phenotype.
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2.
Primary creatine deficiency syndrome as a potential missed diagnosis in children with psychomotor delay and seizure: case presentation with two novel variants and literature review.
Rostami, P, Hosseinpour, S, Ashrafi, MR, Alizadeh, H, Garshasbi, M, Tavasoli, AR
Acta neurologica Belgica. 2020;(3):511-516
Abstract
Creatine is the main source of energy for the brain. Primary creatine deficiency syndromes (PCDSs) are inborn error of metabolism of creatine synthesis. Symptoms of central nervous system involvement are the most common clinical manifestations in these disorders. We reviewed medical records of all genetically confirmed patients diagnosed by whole exome sequencing who were referred to Myelin and Neurodegenerative Disorders Clinic, Children's Medical Center, Tehran, Iran, from May 2016 to Dec 2018. A literature review was conducted on clinical and genomic variability of PCDS to compare our patients with previously reported cases. We report two patients with creatine deficiency among a cohort of 550 registered cases out of which 200 patients had a genetically confirmed neurodegenerative disorder diagnosis. The main complain in the first patient with creatine transporter (CRTR) deficiency was seizure and genetic study in this patient identified a novel hemizygote variant of "c.92 > T; p.Pro31Leu" in the first exon of SLC6A8 gene. The second patient with guanidinoacetate methyltransferase (GAMT) deficiency had an unknown motor and speech delay as the striking manifestation and molecular assay revealed a novel homozygote variant of "c.134G > A; p.Trp45*" in the first exon of GAMT gene. PCDSs usually are associated with nonspecific neurologic symptoms. The first presented case had a mean delayed diagnosis of 5 years. Therefore, in children with unexplained neurologic features including developmental delay and/or regression, mental disability and repeated seizures without any significant findings in metabolic studies, PCDSs can be considered as a differential diagnosis and molecular analysis can be helpful for the precise diagnosis and treatment.
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3.
Primrose syndrome: a phenotypic comparison of patients with a ZBTB20 missense variant versus a 3q13.31 microdeletion including ZBTB20.
Juven, A, Nambot, S, Piton, A, Jean-Marçais, N, Masurel, A, Callier, P, Marle, N, Mosca-Boidron, AL, Kuentz, P, Philippe, C, et al
European journal of human genetics : EJHG. 2020;(8):1044-1055
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Abstract
Primrose syndrome is characterized by variable intellectual deficiency, behavior disorders, facial features with macrocephaly, and a progressive phenotype with hearing loss and ectopic calcifications, distal muscle wasting, and contractures. In 2014, ZBTB20 variants were identified as responsible for this syndrome. Indeed, ZBTB20 plays an important role in cognition, memory, learning processes, and has a transcription repressive effect on numerous genes. A more severe phenotype was discussed in patients with missense single nucleotide variants than in those with large deletions. Here, we report on the clinical and molecular results of 14 patients: 6 carrying ZBTB20 missense SNVs, 1 carrying an early truncating indel, and 7 carrying 3q13.31 deletions, recruited through the AnDDI-Rares network. We compared their phenotypes and reviewed the data of the literature, in order to establish more powerful phenotype-genotype correlations. All 57 patients presented mild-to-severe ID and/or a psychomotor delay. Facial features were similar with macrocephaly, prominent forehead, downslanting palpebral fissures, ptosis, and large ears. Hearing loss was far more frequent in patients with missense SNVs (p = 0.002), ectopic calcification, progressive muscular wasting, and contractures were observed only in patients with missense SNVs (p nonsignificant). Corpus callosum dysgenesis (p = 0.00004), hypothyroidism (p = 0.047), and diabetes were also more frequent in this group. However, the median age was 9.4 years in patients with deletions and truncating variant compared with 15.1 years in those with missense SNVs. Longer follow-up will be necessary to determine whether the phenotype of patients with deletions is also progressive.
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4.
Understanding the genetic basis of congenital insensitivity to pain.
Drissi, I, Woods, WA, Woods, CG
British medical bulletin. 2020;(1):65-78
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Abstract
INTRODUCTION OR BACKGROUND Congenital insensitivity to pain (CIP) is caused by extremely rare Mendelian genetic disorders. CIP individuals demonstrate the unexpectedly severe consequences of painlessness. Although only a small number of causative conditions and genes are known, most have led to profound insights into human nociception. CIP gene discovery is catalyzing the manufacture of completely new classes of analgesics, and these are needed as alternatives to synthetic highly potent opioids. SOURCES OF DATA Pubmed.gov peer-reviewed journal articles and reviews. AREAS OF AGREEMENT The importance of nerve growth factor-tropomyosin receptor kinase A (NGF-TRKA) signalling for nociceptor genesis and subsequent pain sensing.New analgesics can be generated from knowledge of the NGF-TRKA nociceptor pathway.Increased susceptibility to Staphylococcus aureus infection is a consequence of deficient NGF-TRKA signalling.Mutations in the voltage-gated sodium channels SCN9A and SCN11A can cause congenital painlessness, and in contradistinction, other mutations can cause episodic neuropathic pain. SCN9A/Nav1.7 is an analgesic target. SCN11A/Nav1.9 is unlikely to be an analgesic target.There are further Mendelian causes of painlessness to be discovered. AREAS OF CONTROVERSY Which NGF-TRKA intracellular signalling pathways operate in nociceptor development and which in post-natal pain sensing?Why have no clinically effective Nav1.7 antagonist been generated? SCN9A-CIP causes analgesia, at least in part, through endogenous opioids.Why do all CIP phenotypes involve a complete loss of all types of nociception? AREAS TIMELY FOR DEVELOPING RESEARCH PRDM12 as an analgesic target.Discovery of the function and analgesic potential of new CIP genes.Can NGF-TRKA be used in the treatment of S. aureus?
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5.
Stop testing for autoantibodies to the VGKC-complex: only request LGI1 and CASPR2.
Michael, S, Waters, P, Irani, SR
Practical neurology. 2020;(5):377-384
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Abstract
Autoantibodies to leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein like-2 (CASPR2) are associated with clinically distinctive syndromes that are highly immunotherapy responsive, such as limbic encephalitis, faciobrachial dystonic seizures, Morvan's syndrome and neuromyotonia. These autoantibodies target surface-exposed domains of LGI1 or CASPR2, and appear to be directly pathogenic. In contrast, voltage-gated potassium channel (VGKC) antibodies that lack LGI1 or CASPR2 reactivities ('double-negative') are common in healthy controls and have no consistent associations with distinct syndromes. These antibodies target intracellular epitopes and lack pathogenic potential. Moreover, the clinically important LGI1 and CASPR2 antibodies comprise only ~15% of VGKC-positive results, meaning that most VGKC-antibody positive results mislead rather than help. Further, initial VGKC testing misses some cases that have LGI1 and CASPR2 antibodies. These collective observations confirm that laboratories should stop testing for VGKC antibodies and instead, test only for LGI1 and CASPR2 antibodies. This change in practice will lead to significant patient benefit.
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Refining the Primrose syndrome phenotype: A study of five patients with ZBTB20 de novo variants and a review of the literature.
Cleaver, R, Berg, J, Craft, E, Foster, A, Gibbons, RJ, Hobson, E, Lachlan, K, Naik, S, Sampson, JR, Sharif, S, et al
American journal of medical genetics. Part A. 2019;(3):344-349
Abstract
Primrose syndrome is a rare autosomal dominant condition caused by heterozygous missense variants within ZBTB20. Through an exome sequencing approach (as part of the Deciphering Developmental Disorders [DDD] study) we have identified five unrelated individuals with previously unreported, de novo ZBTB20 pathogenic missense variants. All five missense variants targeted the C2H2 zinc finger domains. This genotype-up approach has allowed further refinement of the Primrose syndrome phenotype. Major characteristics (>90% individuals) include an intellectual disability (most frequently in the moderate range), a recognizable facial appearance and brain MRI abnormalities, particularly abnormalities of the corpus callosum. Other frequent clinical associations (in 50-90% individuals) include sensorineural hearing loss (83%), hypotonia (78%), cryptorchidism in males (75%), macrocephaly (72%), behavioral issues (56%), and dysplastic/hypoplastic nails (57%). Based upon these clinical data we discuss our current management of patients with Primrose syndrome.
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MYT1L mutation in a patient causes intellectual disability and early onset of obesity: a case report and review of the literature.
Al Tuwaijri, A, Alfadhel, M
Journal of pediatric endocrinology & metabolism : JPEM. 2019;(4):409-413
Abstract
Background Obesity has become one of the greatest health risks worldwide. Recently, there was an explosion of information regarding the role of the central nervous system (CNS) in the development of monogenic and syndromic obesity. Case presentation Over the last decade, terminal and interstitial submicroscopic deletions of copy number variants (CNVs) in 2p25.3 and single nucleotide variants (SNVs) in myelin transcription factor 1 like (MYT1L) were detected by genome-wide array analysis and whole exome sequencing (WES) in patients with a nonspecific clinical phenotype that commonly includes intellectual disability (ID), early onset of obesity and speech delay. Here, we report the first Saudi female patient with mild to moderate ID, early onset of obesity and speech delay associated with a de novo pathogenic SNV in the MYT1L gene (c. 1585G>A [Gly529Arg]), which causes an amino acid change from Gly to Arg at position 529 that leads to mental retardation, autosomal dominant 39.
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The role of new adipokines in gestational diabetes mellitus pathogenesis.
Mierzyński, R, Poniedziałek-Czajkowska, E, Dłuski, D, Leszczyńska-Gorzelak, B
Ginekologia polska. 2018;(4):221-26
Abstract
Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition dur-ing pregnancy. Explanation of the GDM pathogenesis is important due to preventing gestational complications. During pregnancy there are significant changes in maternal metabolism. Many of these changes are influenced by different adi-pokines produced in the placenta and adipose tissue. The exact role of adipokines in the pathogenesis of GDM remains still unknown. Several adipokines have been analysed throughout gestation and their levels have been suggested as biomarkers of maternal-perinatal outcomes. Some of them have been postulated as significant in the pathogenesis of pregnancy complications like GDM. This report aims to review some of the recent topics of adipokine research that may be of particular importance in patho-physiology and diagnosis of gestational diabetes mellitus. Because of manuscript length limitations, after thorough literature review and in view of the recent evidence, we focus on the one of the most well-known adipokine: adiponectin, and not so well-studied: nesfatin-1, chemerin, ghrelin, and CTRP 1.
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9.
LGI1, CASPR2 and related antibodies: a molecular evolution of the phenotypes.
Binks, SNM, Klein, CJ, Waters, P, Pittock, SJ, Irani, SR
Journal of neurology, neurosurgery, and psychiatry. 2018;(5):526-534
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Abstract
Recent biochemical observations have helped redefine antigenic components within the voltage-gated potassium channel (VGKC) complex. The related autoantibodies may be now divided into likely pathogenic entities, which target the extracellular domains of leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-like 2 (CASPR2), and species that target intracellular neuronal components and are likely non-pathogenic. This distinction has enhanced clinical practice as direct determination of LGI1 and CASPR2 antibodies offers optimal sensitivity and specificity. In this review, we describe and compare the clinical features associated with pathogenic LGI1 and CASPR2 antibodies, illustrate emerging laboratory techniques for antibody determination and describe the immunological mechanisms that may mediate antibody-induced pathology. We highlight marked clinical overlaps between patients with either LGI1 or CASPR2 antibodies that include frequent focal seizures, prominent amnesia, dysautonomia, neuromyotonia and neuropathic pain. Although occurring at differing rates, these commonalities are striking and only faciobrachial dystonic seizures reliably differentiate these two conditions. Furthermore, the coexistence of both LGI1 and CASPR2 antibodies in an individual occurs surprisingly frequently. Patients with either antibody respond well to immunotherapies, although systematic studies are required to determine the magnitude of the effect beyond placebo. Finally, data have suggested that CASPR2 and LGI1 modulation via genetic or autoimmune mechanisms may share common intermediate molecules. Taken together, the biochemical distinction of antigenic targets has led to important clinical advances for patient care. However, the striking syndrome similarities, coexistence of two otherwise rare antibodies and molecular insights suggest the VGKC complex may yet be a common functional effector of antibody action. Hence, we argue for a molecular evolution alongside a clinical and phenotypic re-evaluation.
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Novel transmitters in brain stem vagal neurocircuitry: new players on the pitch.
Bülbül, M, Travagli, RA
American journal of physiology. Gastrointestinal and liver physiology. 2018;(1):G20-G26
Abstract
The last few decades have seen a major increase in the number of neurotransmitters and neuropeptides recognized as playing a role in brain stem neurocircuits, including those involved in homeostatic functions such as stress responsiveness, gastrointestinal motility, feeding, and/or arousal/wakefulness. This minireview will focus on the known physiological role of three of these novel neuropeptides, i.e., apelin, nesfatin-1, and neuropeptide-S, with a special emphasis on their hypothetical roles in vagal signaling related to gastrointestinal motor functions.