RESUMO
BACKGROUND: Deficiencies in the thyroid hormone transporter monocarboxylate 8 (MCT8) due to pathogenic variants in the SLC16A2 gene (OMIM 300095) result in a complex phenotype with main endocrine and neurologic symptoms. This rare disorder, named Allan-Herndon-Dudley syndrome (AHDS) (OMIM 300523), is inherited in an X-linked trait. One of the prominent features of AHDS is the presence of movement disorders (MD), which are complex and carry a significant burden of the disease. CASES: Patient 1: male with hypotonia since birth, developmental delay, dystonic posturing at 4 months and at 15 months, and startle reaction developed with sensory stimuli. Patient 2: male, at 2 months, shows hypotonia and developmental delay, paroxysmal episodes triggered by a stimulus with sudden blush, tonic asymmetric posture, and no epileptiform activity. At 10 months, generalized dystonic posturing. Patient 3: typical neurodevelopmental milestones until 6 months; at 24 months, dystonia, startle reaction, and upper motoneuron signs. CONCLUSIONS: We aim to describe our patients diagnosed with AHDS, focusing on MD phenomenology and strengthening the phenotype-genotype correlations for this rare condition.
Assuntos
Hipotonia Muscular , Humanos , Masculino , Hipotonia Muscular/genética , Transportadores de Ácidos Monocarboxílicos/genética , Transportadores de Ácidos Monocarboxílicos/deficiência , Atrofia Muscular/genética , Atrofia Muscular/patologia , Lactente , Transtornos dos Movimentos/genética , Deficiência Intelectual Ligada ao Cromossomo X/genética , Deficiência Intelectual Ligada ao Cromossomo X/diagnóstico , Simportadores/genética , Simportadores/deficiência , Colômbia , Pré-Escolar , Fenótipo , Deficiências do Desenvolvimento/genéticaRESUMO
Early onset myopathies are a clinically and histologically heterogeneous monogenic diseases linked to approximately 90 genes. Molecular diagnosis is challenging, especially in patients with a mild phenotype. We describe a 26-year-old man with neonatal hypotonia, motor delay and seizures during infancy, and non-progressive, mild muscular weakness in adulthood. Serum Creatine kinase level was normal. Whole-body muscle MRI showed thin muscles, and brain MRI was unremarkable. A deltoid muscle biopsy showed glycogen storage. WGS revealed a de novo 1.4 Mb-deletion of chromosome 14, confirmed by Array-CGH. This microdeletion causes the loss of ten genes including RALGAPA1, encoding for RalA, a regulator of glucose transporter 4 (GLUT4) expression at the membrane of myofibers. GLUT4 was overexpressed in patient's muscle. Here we highlight the importance to search for chromosomal alterations in the diagnostic workup of early onset myopathies.
Assuntos
Glicogênio , Doenças Musculares , Masculino , Recém-Nascido , Humanos , Adulto , Cromossomos Humanos Par 14 , Doenças Musculares/genética , Hipotonia Muscular/genética , Fenótipo , Proteínas do Tecido Nervoso/genética , Proteínas Ativadoras de GTPase/genéticaRESUMO
OBJECTIVE: To describe the clinical presentation and long-term clinical features of a molecularly confirmed cohort with Cohen syndrome. STUDY DESIGN: Twelve patients with Cohen syndrome aged 0.2-13.9 years from 8 families with a median follow-up of 7 years were enrolled to the study. Genetic analyses were made by VPS13B and whole-exome sequencing analyses. RESULTS: Biallelic VPS13B variants, including 3 nonsense, 1 frameshift, and 1 splice-site variant, and a multiexon deletion were detected. Prader-Willi syndrome-like features such as hypotonia, small hands, round face with full cheeks, almond-shaped eyes, and micrognathia were observed in all infantile patients. Beginning from age 4 years, it was noticed that the face gradually elongated and became oval. The typical facial features of Cohen syndrome such as a long face, beak-shaped nose, and open-mouth appearance with prominent upper central incisors became evident at age 9. Other Cohen syndrome features including retinopathy (11/11), neutropenia (11/12), truncal obesity (5/12), and myopia (5/11) were detected at the median ages of 7.8, 7, 7.5, and 5 years, respectively. Eleven patients aged older than 5 years at their last examination had severe speech delay. CONCLUSIONS: A differential diagnosis of Cohen syndrome in the infancy should be made with Prader-Willi syndrome, and that the typical facial features for Cohen syndrome is prominent at age 9 years, when retinopathy, neutropenia, and truncal obesity become evident. Moreover, adding the severe speech delay to the diagnostic criteria should be considered.
Assuntos
Deficiência Intelectual , Transtornos do Desenvolvimento da Linguagem , Microcefalia , Miopia , Neutropenia , Síndrome de Prader-Willi , Degeneração Retiniana , Humanos , Criança , Hipotonia Muscular/diagnóstico , Hipotonia Muscular/genética , Proteínas de Transporte Vesicular/genética , Microcefalia/diagnóstico , Microcefalia/genética , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Degeneração Retiniana/genética , Miopia/diagnóstico , Miopia/genética , Obesidade/diagnóstico , Obesidade/genéticaRESUMO
Birk-Barel intellectual disability dimorphism syndrome, also referred to as KCNK9 imprinting syndrome, is an exceedingly rare condition described in under 20 cases that presents with intellectual disability, hypotonia, scoliosis, dysphonia, dysphagia, and craniofacial dysmorphic features. The condition follows an autosomal dominant pattern of inheritance in the maternally expressed KCNK9 gene on chromosome 8. Due to the complexity of presentation, patients with Birk-Barel syndrome are optimally managed by a multidisciplinary team including a craniofacial surgeon. Previously described craniofacial dysmorphic features include micrognathia, cleft palate, dolichocephaly, broad nasal tip, and broad philtrum, among others. Here the authors describe a genetically confirmed case that has been managed in our institution's multidisciplinary cleft and craniofacial clinic. The authors aim to discuss Birk-Barel syndrome for a surgical and craniofacial audience with considerations for operative management in the context of a multidisciplinary team.
Assuntos
Anormalidades Craniofaciais , Deficiência Intelectual , Canais de Potássio de Domínios Poros em Tandem , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/cirurgia , Caracteres Sexuais , Anormalidades Craniofaciais/genética , Anormalidades Craniofaciais/cirurgia , Hipotonia Muscular/genética , Síndrome , Canais de Potássio de Domínios Poros em Tandem/genéticaRESUMO
C-terminal binding proteins (CtBP1/2) are transcriptional coregulators that play a significant role during vertebrate neurodevelopment. This systematic review aims to identify case reports with genetic variants in CTBP1 and CTBP2 associated with brain development syndromes.We screened different databases (PubMed, Scopus, Google Scholar, LILACS) by systematically searching journals and checking reference lists and citations of background papers. We found fourteen cases (10 males) from five papers carrying two pathogenic, heterozygous variants in the CTBP1 gene (13 individuals carried the missense mutation c.991C T, p.Arg342Trp, and one subject carrying the 2-base pair deletion c.1315_1316delCA, p.Gln439ValfsTer84). These mutations were de novo in 13 cases and one case of maternal germinal mosaicism. Two variants are in the same domain of the protein: Pro-Leu-Asp-Leu-Ser (PLDLS) C terminal. Patients with these mutations exhibit a phenotype with intellectual disability, HADDTS syndrome (hypotonia, ataxia, developmental delay, and tooth enamel defects), and cerebellar volume loss. We did not identify reported cases associated with homozygous mutations harbored in CTBP1. We did not identify any report of neurodevelopment phenotypes associated with heterozygous or homozygous CTBP2 mutations. Due to CTBP2/RIBEYE being a gene with dual function, identifying and interpreting the potential pathogenic variants is challenging.Further, homozygous mutations in the CTBP2 gene may be lethal. The mechanisms involved in the pathogenesis of neurodevelopment due to variants of these proteins have not yet been elucidated, despite some functional evidence. Further studies should be conducted to understand these transcription factors and their interaction with each other and their partners.
Assuntos
Oxirredutases do Álcool , Proteínas Correpressoras , Hipotonia Muscular , Fatores de Transcrição , Humanos , Oxirredutases do Álcool/genética , Ataxia/genética , Proteínas Correpressoras/genética , Hipotonia Muscular/genética , Mutação , Mutação de Sentido Incorreto , Fatores de Transcrição/genéticaRESUMO
Allan-Herndon-Dudley syndrome is a rare X-linked genetic disorder, caused by a deficiency of the monocarboxylate transporter 8 (MCT8), a specific transporter of thyroid hormones, with functions mainly at the brain level. The syndrome produces an early onset of severe neurological disorder, in which hypotonia predominates. OBJECTIVE: To present a rare case with an unexpected diagnosis, highlighting the usefulness of requesting a complete thyroid profile in every hypotonic male infant without a specific cause. CLINICAL CASE: A 10-month-old male infant with severe axial and peripheral hypotonia, global weakness with little spontaneous mobility, without head support or stable sitting. Complete metabolic and peripheral neurophysiological studies were performed. Genetic studies for spinal muscular atrophy, Prader Willi syndrome, and myotonic dystrophy were also performed. The trio exome analysis detected a probably pathogenic variant c.359C>T;p.(Ser120Phe), hemizygous in exon 1 of the SLC16A2 gene, inherited from the mother. Thyroid abnormalities as increased free triiodothyronine (T3) and thyroid-stimulating hormone (TSH), and delayed myelination were ob served. CONCLUSIONS: MCT8 deficiency should be considered in the case of the male infant with unex plained hypotonia and weakness without a determined cause. The diagnosis is guided by a thyroid profile including free T3 hormone, because it presents a characteristic thyroid profile with decreased free thyroxine (T4), increased free T3, and normal or slightly elevated TSH levels. In this case, the implementation of the trio exome analysis allows establishing an early certain diagnosis.
Assuntos
Hipotonia Muscular , Simportadores , Humanos , Lactente , Masculino , Deficiência Intelectual Ligada ao Cromossomo X , Transportadores de Ácidos Monocarboxílicos/genética , Hipotonia Muscular/etiologia , Hipotonia Muscular/genética , Atrofia Muscular , Simportadores/genética , Hormônios Tireóideos , TireotropinaRESUMO
In 2017, Mattiolli et al. and Yan et al. described a series of patients with clinical findings essentially characterized by intellectual disabilities, ptosis, hypotonia, epilepsy, and weakness. They also found in these patients distinct heterozygous mutations in the BRPF1 gene, which plays a role in epigenetic regulation by promoting histone acetylation. The disease is known as Intellectual Developmental Disorder with Dysmorphic Facies and Ptosis (IDDDFP, OMIM #617333). Later, another 20 patients were also described by distinct reports, suggesting IDDDFP could be a more frequent cause of intellectual disability as it was thought before. Here, we describe a patient with normal intellectual development who had congenital ptosis, hypotonia, muscular weakness, atlanto-axial malformation, and pyramidal at the neurological examination. The patient has a rare nonsense variant on exon 3 of BRPF1 gene. We also describe a phenotypic amplification for conditions related to deficiency in histone modifications.
Assuntos
Blefaroptose , Deficiência Intelectual , Proteínas Adaptadoras de Transdução de Sinal/genética , Blefaroptose/diagnóstico , Blefaroptose/genética , Proteínas de Ligação a DNA/genética , Epigênese Genética , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Hipotonia Muscular/genética , Mutação , SíndromeRESUMO
BACKGROUND: Amyotrophic Lateral Sclerosis (ALS) is a rare, progressive, and fatal neurodegenerative disease due to upper and lower motor neuron involvement with symptoms classically occurring in adulthood with an increasing recognition of juvenile presentations and childhood neurodegenerative disorders caused by genetic variants in genes related to Amyotrophic Lateral Sclerosis. The main objective of this study is detail clinical, radiological, neurophysiological, and genetic findings of a Brazilian cohort of patients with a recent described condition known as Spastic Tetraplegia and Axial Hypotonia (STAHP) due to SOD1 deficiency and compare with other cases described in the literature and discuss whether the clinical picture related to SOD1 protein deficiency is a new entity or may be represent a very early-onset form of Amyotrophic Lateral Sclerosis. METHODS: We conducted a case series report which included retrospective data from five Brazilian patients with SOD1 protein deficiency of a Brazilian reference center for Neuromuscular Disorders. Clinical data were obtained from a review of the medical records and descriptive statistics and variables were summarized using counts and percentages of the total population. RESULTS: All 5 patients presented with a childhood-onset neurodegenerative disorders characterized by spastic tetraplegia with axial hypotonia in all cases, with gestational history showing polyhydramnios in 4/5 and intrauterine growth restriction in 3/5 patients, with most patients initially presenting a normal motor development until the six month of life or during the first year followed by a rapidly progressive motor decline with severe dysphagia and respiratory insufficiency in all patients accompanied by cognitive impairment in 3/5 patients. All patients were homozygous for the c.335dupG (p.Cys112Trpfs*11) mutation in the SOD1 gene with completely decreased enzyme activity. CONCLUSIONS: This case series is the biggest data collection of the new recent clinical entity described as Spastic Tetraplegia and Axial Hypotonia (STAHP) due to SOD1 deficiency.
Assuntos
Esclerose Lateral Amiotrófica , Hipotonia Muscular , Superóxido Dismutase-1 , Adulto , Esclerose Lateral Amiotrófica/genética , Criança , Humanos , Hipotonia Muscular/genética , Mutação/genética , Quadriplegia/genética , Estudos Retrospectivos , Superóxido Dismutase-1/genéticaRESUMO
NALCN encodes a sodium ion leak channel expressed in the nervous system that conducts a persistent influx of sodium ions to facilitate action potential formation. Homozygous or compound heterozygous loss of function variants in NALCN cause infantile hypotonia with psychomotor retardation and characteristic facies-1 (IHPRF1; OMIM 615419). Through exome and Sanger sequencing, we found two siblings of Afro-Caribbean ancestry who are homozygous for a known NALCN pathogenic variant, p.Arg735Ter, leading to failure to thrive, severe hypotonia, and dolichocephaly. The older sibling died suddenly without a known etiology after evaluation but before molecular diagnosis. An international collaboration originating from a resource limited Caribbean island facilitated molecular diagnosis. Due to its small population, geographical isolation, and low socioeconomic status, the island lacks many specialty medical services, including clinical genetics. Descriptions of genetic disorders affecting individuals of Afro-Caribbean ancestry are rarely reported in the medical literature. Diagnosis of IHPRF1 is important, as individuals with biallelic pathogenic NALCN variants are severely affected and potentially are at risk for cardiorespiratory arrest. Additionally, knowing the pathogenic variants allows the possibility of prenatal or preimplantation genetic diagnosis.
Assuntos
Predisposição Genética para Doença , Canais Iônicos/genética , Proteínas de Membrana/genética , Hipotonia Muscular/genética , Transtornos Psicomotores/genética , Região do Caribe , Exoma/genética , Feminino , Homozigoto , Humanos , Lactente , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Masculino , Hipotonia Muscular/diagnóstico , Hipotonia Muscular/patologia , Mutação de Sentido Incorreto/genética , Transtornos Psicomotores/diagnóstico , Transtornos Psicomotores/patologia , IrmãosRESUMO
Alteration of the KPTN gene, responsible for the coding of kaptin (a protein involved in actin cytoskeletal dynamics), causes a syndrome characterized by macrocephaly, neurodevelopmental delay and epileptic seizures. We report the first Brazilian case of KPTN gene variation, previously described in nine subjects from four interlinked families from an Amish community in Ohio, two Estonian siblings and a 9-year-old boy from Kansas City. We report a case of KPTN-related syndrome in a 5-year-old child which presented macrocephaly, muscular hypotonia, and global development delay. The neurological examination revealed below-expected performance in coordination and balance tests, dyspraxia, and hand-mouth synkinesia. Expressive language was characterized by phono-articulatory imprecision, abundance of phonological processes and morphosyntactic immaturity. Neuropsychological assessment revealed intellectual disability with impairment of verbal and executive functions. Exome sequencing was performed. Analysis revealed a homozygous 2-nucleotide duplication c.597_598dup p.(Ser200Ilefs*55) in the KPTN gene, which is predicted to lead to a translational frameshift and formation of a premature stop codon. The phenotypic profile is similar to the cases described in the other families. Presence of macrocephaly and delayed development indicate the possibility of KPTN gene variation. Genetic testing should be carried out at an early stage in order to reach a timely diagnosis.