A CASE REPORT OF JUVENILE FORM OF METACHROMATIC LEUKODYSTROPHY

Metachromatic Leukodystrophy is a lysosomal storage autosomal recessive disease characterized by arylsulphatase enzyme deficiency, with central and peripheral demyelination. We report a case of a 15-year-old girl with 6 months history of progressive muscular weakness, poor school performance, gradual memory loss and gait disturbance. Neurological examination was grossly normal, except mild muscle wastage in both upper and lower limbs and slight reduction of power globally in all limbs. Routine bloods including a lumbar puncture was normal and the diagnosis of metachromatic leukodystrophy was made on the findings of magnetic resonance imaging (MRI) brain.

Paracoccidioidomycosis in an Elderly Simulating Cholangiocarcinoma

Paracoccidioidomycosis, the most prevalent deep mycosis in Latin America, is caused by dimorphic species of the genus Paracoccidioides, affects predominantly male rural workers between 30-50 years of age and is an important cause of morbidity and mortality. It can present in two clinical forms: acute/subacute or chronic. In rare cases paracoccidioidomycosis may simulate neoplasia and must be considered as a differential diagnosis of intra-abdominal tumors in endemic areas. We report an exuberant case of subacute paracoccidioidomycosis in an elderly lady, although it is more frequent in the juvenile form. Multiple facial skin lesions were associated with a wasting syndrome and extensive adenopathy including in the hepatic area, causing bile duct dilatation simulating a cholangiocarcinoma. Skin histopathology was diagnostic and antifungal treatment allowed complete resolution of cutaneous and systemic lesions, thus highlighting the merit of the dermatologist, who was fundamental for the conclusive diagnosis and institution of specific therapy, resulting in a favorable outcome.

Differential diagnosis of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a disease with an X-linked recessive type of inheritance, belonging to a group of disorders with primary muscle damage, caused by pathogenic variants in the DMD gene and associated with dysfunction of the dystrophin protein. Since DMD is manifested by the gradual development of progressive, mainly proximal muscle weakness, the differential diagnosis is primarily carried out in the group of diseases with muscle damage - myopathies. Among these diseases, the leading candidates for differential diagnosis are hereditary myopathies (limb-girdle muscular dystrophies, facioscapulohumeral dystrophy, congenital muscular dystrophies, glycogenoses - the most common juvenile form of glycogenosis type II (Pompe disease)) and, much less often, congenital myopathies and other conditions of neuromuscular diseases). When conducting a differential diagnosis in a child with suspected DMD, the age of the onset of the disease, early initial clinical manifestations and the development of symptoms as they grow, genealogical analysis, laboratory tests (the level of creatine kinase, aspartate aminotransferase, alanine aminotransferase in blood serum), instrumental (electromyography, magnetic resonance imaging of the brain and muscles) and molecular genetics (polymerase chain reaction, multiplex ligation-dependent probe amplification, next-generation sequencing, Sanger sequencing, etc.) of studies, and in some cases, muscle biopsy data. Knowledge of the nuances of the differential diagnosis allows establishing a genetic diagnosis of DMD as early as possible, which is extremely important for the formation of the prognosis of the disease and the implementation of all available treatment methods, including pathogenetic therapy, and is also necessary for medical and genetic counselling of families with DMD patients.

Juvenile form of alexander disease caused by a previously undescribed mutation in the GFAP gene. a case report

Alexander disease is a form of leukoencephalopathy caused by mutations in the GFAP gene. There are three forms of the disease: infant, juvenile and adult. We present the clinical case of a patient born in 2004 (16 years old) with a debut of the disease at the age of 4 years with complex ticks. further neurological symptoms progressed and appeared atactic gait, intention tremor by performing coordination tests, muscle hypotension, decreased tendon reflexes, nasal voices, and behavior changes.Magnetic resonance imaging revealed changes in the white matter of both frontal lobes. An analysis was made of 59 genes of the panel “Leukodystrophy/leukoencephalopathy” by the method of mass parallel sequencing on the Ion S5. A mutation of the GFAP gene (Nm_002055), 4 exon c.758C>A, p.ALA253Asp in a heterozygous state, not described in Human Gene mutation Database, was detected. The patient was confirmed to have a diagnosis of Alexander disease. According to tractography, a decrease in the number of fibers in the frontal lobes was found.The patient is currently receiving symptomatic treatment.

Renal Ciliopathies: Sorting Out Therapeutic Approaches for Nephronophthisis

Nephronophthisis (NPH) is an autosomal recessive ciliopathy and a major cause of end-stage renal disease in children. The main forms, juvenile and adult NPH, are characterized by tubulointerstitial fibrosis whereas the infantile form is more severe and characterized by cysts. NPH is caused by mutations in over 20 different genes, most of which encode components of the primary cilium, an organelle in which important cellular signaling pathways converge. Ciliary signal transduction plays a critical role in kidney development and tissue homeostasis, and disruption of ciliary signaling has been associated with cyst formation, epithelial cell dedifferentiation and kidney function decline. Drugs have been identified that target specific signaling pathways (for example cAMP/PKA, Hedgehog, and mTOR pathways) and rescue NPH phenotypes in in vitro and/or in vivo models. Despite identification of numerous candidate drugs in rodent models, there has been a lack of clinical trials and there is currently no therapy that halts disease progression in NPH patients. This review covers the most important findings of therapeutic approaches in NPH model systems to date, including hypothesis-driven therapies and untargeted drug screens, approached from the pathophysiology of NPH. Importantly, most animal models used in these studies represent the cystic infantile form of NPH, which is less prevalent than the juvenile form. It appears therefore important to develop new models relevant for juvenile/adult NPH. Alternative non-orthologous animal models and developments in patient-based in vitro model systems are discussed, as well as future directions in personalized therapy for NPH.

A knockout mutation associated with juvenile paroxysmal dyskinesia in Markiesje dogs indicates SOD1 pleiotropy

A juvenile form of paroxysmal dyskinesia segregated in the Markiesje dog breed. Affected pups exhibited clinical signs of a severe tetraparesis, dystonia, cramping and falling over when trying to walk. In most cases, the presentation deteriorated within weeks and elective euthanasia was performed. Pedigree analysis indicated autosomal recessive inheritance. Genome-wide association and homozygosity mapping of 5 affected dogs from 3 litters identified the associated locus on chromosome 31 in the region of SOD1. The DNA sequence analysis of SOD1 showed that the patients were homozygous for a frameshift mutation in the fourth codon. None of the other analyzed dogs of the breed was homozygous for the mutation, indicating full penetrance of the genetic defect. Mutations in SOD1 are known to cause recessive degenerative myelopathy in middle-aged dogs with low penetrance and dominant amyotrophic lateral sclerosis in humans with variable age of onset. Our findings are similar to recent observations in human patients that a loss of function mutation in SOD1 leads to a juvenile neurologic disease distinct from amyotrophic lateral sclerosis.

STIM2 Mediates Excessive Store-Operated Calcium Entry in Patient-Specific iPSC-Derived Neurons Modeling a Juvenile Form of Huntington's Disease

Huntington's disease (HD) is a severe autosomal-dominant neurodegenerative disorder caused by a mutation within a gene, encoding huntingtin protein. Here we have used the induced pluripotent stem cell technology to produce patient-specific terminally differentiated GABA-ergic medium spiny neurons modeling a juvenile form of HD (HD76). We have shown that calcium signaling is dramatically disturbed in HD76 neurons, specifically demonstrating higher levels of store-operated and voltage-gated calcium uptakes. However, comparing the HD76 neurons with the previously described low-repeat HD models, we have demonstrated that the severity of calcium signaling alterations does not depend on the length of the polyglutamine tract of the mutant huntingtin. Here we have also observed greater expression of huntingtin and an activator of store-operated calcium channels STIM2 in HD76 neurons. Since shRNA-mediated suppression of STIM2 decreased store-operated calcium uptake, we have speculated that high expression of STIM2 underlies the excessive entry through store-operated calcium channels in HD pathology. Moreover, a previously described potential anti-HD drug EVP4593 has been found to attenuate high levels of both huntingtin and STIM2 that may contribute to its neuroprotective effect. Our results are fully supportive in favor of the crucial role of calcium signaling deregulation in the HD pathogenesis and indicate that the cornerstone of excessive calcium uptake in HD-specific neurons is a calcium sensor and store-operated calcium channels activator STIM2, which should become a molecular target for medical treatment and novel neuroprotective drug development.

Familial ALS Type 25 – A Brazillian Case Serie

Introduction: Familial Amyotrophic Lateral Sclerosis (fALS) represent 5-10% of ALS patients. Different mutations in the N-terminal motor or coiled-coil domains of the kinesin family member 5A (KIF5A) cause Hereditary Spastic Paraplegia Type 10 (HSP10), Charcot-Marie-Tooth 2 (CMT2), Neonatal Intractable Myoclonus and more recently described fALS Type 25. Previous described phenotypes are very similar to the sporadic type, except from the long course of disease. Methods: We describe four Brazillian patients, under clinical follow-up on two Neuromuscular services with genetic diagnosis of fALS25. Results: Four diferent fALS25 are described. Two brothers and two unrelated patients, with distinct features, three males and one female, age range from 72 to 24; age of onset ranged from 62 to 22. The genetic mutations were the following: simple heterozygous pathogenic variant c.1651C>G (p. Leu551Val), simple heterozygous pathogenic variant c.2953G>A (p. Gly985Ser) and pathogenic variant c.484C>T (p.Arg162Trp); all of KIF5A gene (fALS25). Only one patient presented with similar phenoptype and age of onset as sporadic ALS (sALS), the two brothers presented the symptoms at the ages of 28 and 30, the female patient at 22. All patients still walk without assistence after the diagnosis. All patients showed classic superior and inferior motor neuron involvement signs, but one brother had a mild limb ataxia. The three younger patients had MRI with no specific findings, except from subtle cortical atrophy in one brother, and mild vermis and corpus callosum atrophy on the other brother. Only the female patient had negative familiar history. Conclusions: fALS25 should be suspected in patient with fALS and longer course disease. Mutations KIF5A gene must be remembered either in juvenile form of ALS.

Current Insights in Elucidation of Possible Molecular Mechanisms of the Juvenile Form of Batten Disease

The neuronal ceroid lipofuscinoses (NCLs) collectively constitute one of the most common forms of inherited childhood-onset neurodegenerative disorders. They form a heterogeneous group of incurable lysosomal storage diseases that lead to blindness, motor deterioration, epilepsy, and dementia. Traditionally the NCL diseases were classified according to the age of disease onset (infantile, late-infantile, juvenile, and adult forms), with at least 13 different NCL varieties having been described at present. The current review focuses on classic juvenile NCL (JNCL) or the so-called Batten (Batten-Spielmeyer-Vogt; Spielmeyer-Sjogren) disease, which represents the most common and the most studied form of NCL, and is caused by mutations in the CLN3 gene located on human chromosome 16. Most JNCL patients carry the same 1.02-kb deletion in this gene, encoding an unusual transmembrane protein, CLN3, or battenin. Accordingly, the names CLN3-related neuronal ceroid lipofuscinosis or CLN3-disease sometimes have been used for this malady. Despite excessive in vitro and in vivo studies, the precise functions of the CLN3 protein and the JNCL disease mechanisms remain elusive and are the main subject of this review. Although the CLN3 gene is highly conserved in evolution of all mammalian species, detailed analysis of recent genomic and transcriptomic data indicates the presence of human-specific features of its expression, which are also under discussion. The main recorded to date changes in cell metabolism, to some extent contributing to the emergence and progression of JNCL disease, and human-specific molecular features of CLN3 gene expression are summarized and critically discussed with an emphasis on the possible molecular mechanisms of the malady appearance and progression.

Deleterious AGXT Missense Variant Associated with Type 1 Primary Hyperoxaluria (PH1) in Zwartbles Sheep

Severe oxalate nephropathy has been previously reported in sheep and is mostly associated with excessive oxalate in the diet. However, a rare native Dutch breed (Zwartbles) seems to be predisposed to an inherited juvenile form of primary hyperoxaluria and no causative genetic variant has been described so far. This study aims to characterize the phenotype and genetic etiology of the inherited metabolic disease observed in several purebred Zwartbles sheep. Affected animals present with a wide range of clinical signs including condition loss, inappetence, malaise, and, occasionally, respiratory signs, as well as an apparent sudden unexpected death. Histopathology revealed widespread oxalate crystal deposition in kidneys of the cases. Whole-genome sequencing of two affected sheep identified a missense variant in the ovine AGXT gene (c.584G>A; p.Cys195Tyr). Variants in AGXT are known to cause type I primary hyperoxaluria in dogs and humans. Herein, we present evidence that the observed clinicopathological phenotype can be described as a form of ovine type I primary hyperoxaluria. This disorder is explained by a breed-specific recessively inherited pathogenic AGXT variant. Genetic testing enables selection against this fatal disorder in Zwartbles sheep as well as more precise diagnosis in animals with similar clinical phenotype. Our results have been incorporated in the Online Mendelian Inheritance in Animals (OMIA) database (OMIA 001672-9940).