RESUMO
OBJECTIVES: The availability of cell-free (cf) DNA as a prenatal screening tool affords an opportunity for non-invasive identification of sex chromosome aneuploidy (SCA). The aims of this longitudinal study were to investigate the evolution and frequency of both invasive prenatal diagnostic testing, using amniocentesis and chorionic villus sampling (CVS), and the detection of SCA in cfDNA samples from a large unselected cohort in Northern Italy. METHODS: The results of genetic testing from CVS and amniotic fluid samples received from public and private centers in Italy from 1995 to 2021 were collected. Chromosomal analysis was performed by routine Q-banding karyotype. Regression analyses and descriptive statistics were used to determine population data trends regarding the frequency of prenatal diagnostic testing and the identification of SCA, and these were compared with the changes in indication for prenatal diagnostic tests and available screening options. RESULTS: Over a period of 27 years, there were 13 939 526 recorded births and 231 227 invasive procedures were performed, resulting in the prenatal diagnosis of 933 SCAs. After the commercial introduction of cfDNA use in 2015, the frequency of invasive procedures decreased significantly (P = 0.03), while the frequency of prenatal SCA detection increased significantly (P = 0.007). Between 2016 and 2021, a high-risk cfDNA result was the indication for 31.4% of detected sex chromosome trisomies, second only to advanced maternal age. CONCLUSIONS: Our findings suggest that the inclusion of SCA in prenatal cfDNA screening tests can increase the prenatal diagnosis of affected individuals. As the benefits of early ascertainment are increasingly recognized, it is essential that healthcare providers are equipped with comprehensive and evidence-based information regarding the associated phenotypic differences and the availability of targeted effective interventions to improve neurodevelopmental and health outcomes for affected individuals. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.
Assuntos
Aneuploidia , Ácidos Nucleicos Livres , Humanos , Feminino , Gravidez , Incidência , Estudos Longitudinais , Itália/epidemiologia , Diagnóstico Pré-Natal/métodos , Aberrações dos Cromossomos Sexuais , Ácidos Nucleicos Livres/genética , Trissomia , Cariotipagem , Amniocentese , Transtornos Cromossômicos/epidemiologia , Transtornos Cromossômicos/genéticaRESUMO
While the urea cycle disorders (UCDs) classically present in the neonatal stage, they have become increasingly recognized as a rare cause of unexplained hyperammonemic encephalopathy in adults. Many metabolic triggers for late-onset UCDs have been described in the literature including excessive protein intake. In this case series, ten such documented cases are reviewed with analysis of patient demographic, protein load, treatment course, and patient outcome. Common delays in treatment include recognition of hyperammonemia as the cause of encephalopathy and initiation of hemodialysis. In only one case was a diet history used to raise suspicion for a metabolic derangement. Metabolic disorders remain an important consideration in adults presenting with encephalopathy not explained by more common etiologies, and recent and remote dietary history may provide valuable information.
RESUMO
PURPOSE: MELAS syndrome is a mitochondrial disorder typified by recurrent stroke-like episodes, seizures, and progressive brain injury. Abnormal mitochondria have been found in arterial walls implicating a vasculogenic etiology. We have observed abnormal cortical vein T2/FLAIR signal in MELAS patients, potentially representing wall thickening and sluggish flow. We sought to examine the relationship of hyperintense veins and brain lesions in MELAS. METHODS: Imaging databases at two children's hospitals were searched for brain MRIs from MELAS patients. Artifact, sedated exams, and lack of 2D-T2/FLAIR sequences were exclusion criteria. Each exam was assigned a venous score based on number of T2/FLAIR hyperintense veins: 1 = <10, 2 = 10 to 20, 3 = >20. Cumulative brain lesions and venous score in MELAS and aged-matched normal exams were compared by Mann-Whitney test. RESULTS: A total of 106 exams from 14 unique MELAS patients (mean 16 ± 3 years) and 30 exams from normal aged-matched patients (mean 15 ± 3 years) were evaluated. Median venous score between MELAS and control patients significantly differed (3 versus 1; p < 0.001). In the MELAS group, venous score correlated with presence (median = 3) or absence (median = 1) of cumulative brain lesions. In all 8 MELAS patients who developed lesions, venous hyperintensity was present prior to, during, and after lesion onset. Venous score did not correlate with brain lesion acuity. CONCLUSION: Abnormal venous signal correlates with cumulative brain lesion severity in MELAS syndrome. Cortical venous stenosis, congestion, and venous ischemia may be mechanisms of brain injury. Identification of cortical venous pathology may aid in diagnosis and could be predictive of lesion development.
Assuntos
Encéfalo/irrigação sanguínea , Síndrome MELAS/diagnóstico por imagem , Síndrome MELAS/patologia , Veias/diagnóstico por imagem , Veias/patologia , Adolescente , Criança , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Índice de Gravidade de Doença , Adulto JovemRESUMO
BACKGROUND: Bilateral infarcts confined to the globus pallidus are unusual and occur in conjunction with only a few disorders, including isolated methylmalonic acidemia, a heterogeneous inborn error of metabolism. On the basis of neuroradiographic features of metabolic strokes observed in a large cohort of patients with methylmalonic acidemia, we have devised a staging system for methylmalonic acidemia-related globus pallidus infarcts. MATERIALS AND METHODS: Forty patients with isolated methylmalonic acidemia and neurologic symptoms underwent clinical brain MR imaging studies, which included 3D-T1WI. Infarcted globus pallidus segments were neuroanatomically characterized, and infarct volumes were measured. RESULTS: Globus pallidus infarcts were present in 19 patients; all were bilateral, and most were left-dominant. A neuroanatomic scoring system based on the infarct patterns was devised; this revealed a 5-stage hierarchical susceptibility to metabolic infarct, with the posterior portion of the globus pallidus externa being the most vulnerable. Globus pallidus infarct prevalence by methylmalonic acidemia class was the following: cblA (5/7, 71%), cblB (3/7, 43%), mut(o) (10/22, 45%), and mut- (1/4, 25%). Tiny lacunar infarcts in the pars reticulata of the substantia nigra, previously unrecognized in methylmalonic acidemia, were found in 17 patients, 13 of whom also had a globus pallidus infarct. CONCLUSIONS: The staged pattern of globus pallidus infarcts in isolated methylmalonic acidemia suggests a nonuniform, regionally specific cellular susceptibility to metabolic injury, even for patients having milder biochemical phenotypes. In support of this hypothesis, the delineation of lacunar infarcts in the pars reticulata of the substantia nigra, a tissue functionally and histologically identical to the globus pallidus interna, supports the concept of cell-specific pathology.
Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/complicações , Infarto Encefálico/etiologia , Infarto Encefálico/patologia , Globo Pálido/patologia , Estudos de Coortes , Feminino , Humanos , Imageamento por Ressonância Magnética , MasculinoRESUMO
Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive, multiple congenital anomaly syndrome with cognitive impairment and a distinct behavioral phenotype that includes autistic features. SLOS is caused by a defect in 3ß-hydroxysterol Δ(7)-reductase which leads to decreased cholesterol levels and elevated cholesterol precursors, specifically 7- and 8-dehydrocholesterol. However, the pathological processes contributing to the neurological abnormalities in SLOS have not been defined. In view of prior data suggesting defects in SLOS in vesicular release and given the association of altered serotonin metabolism with autism, we were interested in measuring neurotransmitter metabolite levels in SLOS to assess their potential to be used as biomarkers in therapeutic trials. We measured cerebral spinal fluid levels of serotonin and dopamine metabolites, 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid (HVA) respectively, in 21 SLOS subjects. Results were correlated with the SLOS anatomical severity score, Aberrant Behavior Checklist scores and concurrent sterol biochemistry. Cerebral spinal fluid (CSF) levels of both 5HIAA and HVA were significantly reduced in SLOS subjects. In individual patients, the levels of both 5HIAA and HVA were reduced to a similar degree. CSF neurotransmitter metabolite levels did not correlate with either CSF sterols or behavioral measures. This is the first study demonstrating decreased levels of CSF neurotransmitter metabolites in SLOS. We propose that decreased levels of neurotransmitters in SLOS are caused by a sterol-related defect in synaptic vesicle formation and that CSF 5HIAA and HVA will be useful biomarkers in development of future therapeutic trials.
Assuntos
Ácido Homovanílico/líquido cefalorraquidiano , Ácido Hidroxi-Indolacético/líquido cefalorraquidiano , Síndrome de Smith-Lemli-Opitz/líquido cefalorraquidiano , Adolescente , Criança , Pré-Escolar , Colesterol/administração & dosagem , Colesterol/líquido cefalorraquidiano , Estudos Cross-Over , Feminino , Humanos , Masculino , Síndrome de Smith-Lemli-Opitz/fisiopatologia , Vesículas Sinápticas/fisiologiaRESUMO
Holoprosencephaly is the most common malformation of the forebrain and typically results in severe neurocognitive impairment with accompanying midline facial anomalies. Holoprosencephaly is heterogeneous and may be caused by chromosome aberrations or environmental factors, occur in the context of a syndrome or be due to heterozygous mutations in over 10 identified genes. The presence of these mutations may result in an extremely wide spectrum of severity, ranging from brain malformations incompatible with life to individuals with normal brain findings and subtle midline facial differences. Typically, clinicians regard intellectual disability as a sign that a parent or relative of a severely affected patient may be a mildly affected mutation 'carrier' with what is termed microform holoprosencephaly. Here we present 5 patients with clear phenotypic signs of microform holoprosencephaly, all of whom have evidence of above-average intellectual function. In 4 of these 5 individuals, the molecular cause of holoprosencephaly has been identified and includes mutations affecting SHH, SIX3, GLI2, and FGF8. This report expands the phenotypic spectrum of holoprosencephaly and is important in the counseling of patient and affected families.
RESUMO
OBJECTIVE: To systematically review the evidence concerning the diagnostic yield of genetic and metabolic evaluation of children with global developmental delay or intellectual disability (GDD/ID). METHODS: Relevant literature was reviewed, abstracted, and classified according to the 4-tiered American Academy of Neurology classification of evidence scheme. RESULTS AND CONCLUSIONS: In patients with GDD/ID, microarray testing is diagnostic on average in 7.8% (Class III), G-banded karyotyping is abnormal in at least 4% (Class II and III), and subtelomeric fluorescence in situ hybridization is positive in 3.5% (Class I, II, and III). Testing for X-linked ID genes has a yield of up to 42% in males with an appropriate family history (Class III). FMR1 testing shows full expansion in at least 2% of patients with mild to moderate GDD/ID (Class II and III), and MeCP2 testing is diagnostic in 1.5% of females with moderate to severe GDD/ID (Class III). Tests for metabolic disorders have a yield of up to 5%, and tests for congenital disorders of glycosylation and cerebral creatine disorders have yields of up to 2.8% (Class III). Several genetic and metabolic screening tests have been shown to have a better than 1% diagnostic yield in selected populations of children with GDD/ID. These values should be among the many factors considered in planning the laboratory evaluation of such children.
Assuntos
Comitês Consultivos/normas , Deficiências do Desenvolvimento , Testes Genéticos/métodos , Neurologia/normas , Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/genética , Deficiências do Desenvolvimento/metabolismo , Medicina Baseada em Evidências , Saúde da Família , Feminino , Proteína do X Frágil da Deficiência Intelectual/genética , Testes Genéticos/normas , Histona Desmetilases , Proteínas de Homeodomínio/genética , Humanos , Masculino , Erros Inatos do Metabolismo/complicações , Erros Inatos do Metabolismo/diagnóstico , Erros Inatos do Metabolismo/genética , Erros Inatos do Metabolismo/metabolismo , Proteína 2 de Ligação a Metil-CpG/genética , Análise em Microsséries/métodos , Mutação/genética , Proteínas do Tecido Nervoso/genética , Oxirredutases N-Desmetilantes/genética , Proteínas da Membrana Plasmática de Transporte de Neurotransmissores/genética , Fatores de Transcrição/genéticaRESUMO
The Research Challenges in CNS Manifestations of Inborn Errors of Metabolism workshop was designed to address challenges in translating potential therapies for these rare disorders, and to highlight novel therapeutic strategies and innovative approaches to CNS delivery, assessment of effects and directions for the future in the treatment of these diseases. Therapies for the brain in inborn errors represent some of the greatest challenges to translational research due to the special properties of the brain, and of inborn errors themselves. This review covers the proceedings of this workshop as submitted by participants. Scientific, ethical and regulatory issues are discussed, along with ways to measure outcomes and the conduct of clinical trials. Participants included regulatory and funding agencies, clinicians, scientists, industry and advocacy groups.
Assuntos
Pesquisa Biomédica , Sistema Nervoso Central , Erros Inatos do Metabolismo/diagnóstico , Erros Inatos do Metabolismo/terapia , Animais , Pesquisa Biomédica/ética , Pesquisa Biomédica/tendências , Sistema Nervoso Central/patologia , Ensaios Clínicos como Assunto/ética , Humanos , Erros Inatos do Metabolismo/fisiopatologia , Doenças Raras/terapiaRESUMO
Holoprosencephaly (HPE), the most common malformation of the human forebrain, may arise due to interacting genetic and environmental factors. To date, at least 12 contributory genes have been identified. Fibroblast growth factor 8 (Fgf8) belongs to the FGF family of genes expressed in several developmental signaling centers, including the anterior neural ridge, which is implicated in midline anomalies in mice. In humans, FGF8 mutations have been previously reported in facial clefting and in hypogonadotropic hypogonadism, but have not been reported in patients with HPE. We screened 360 probands with HPE for sequence variations in FGF8 using High Resolution DNA Melting (HRM) and sequenced all identified variations. Here we describe a total of 8 sequence variations in HPE patients, including a putative loss-of-function mutation in 3 members of a family with variable forms of classic HPE, and relate these findings to the phenotypes seen in other conditions.
RESUMO
BACKGROUND AND PURPOSE: OTCD, an X-linked disorder, is the most common of the UCDs. Neonatal onset is associated with uniformly poor outcome. Males with late-onset OTCD show deficits in executive function, motor planning, and working memory. A broad phenotype is observed in heterozygous females. A specific neurobehavioral phenotype with white matter dysfunction and impaired attention and working memory has been described. The extent to which the deficits involve specific pathways in the brain is unknown. We hypothesized that DTI would disclose white matter microstructure in OTCD correlating with cognitive deficits. MATERIALS AND METHODS: Nineteen adults with partial OTCD and 18 adult control subjects ages 19-59 years participated. MR imaging was performed by using a 3T whole-body scanner. Anisotropy was calculated from the eigenvalues of the diffusion tensor by using the FA metric and was compared between the study and control groups. RESULTS: FA of the frontal white matter was significantly decreased in subjects, indicating changes in white matter microstructure. There was an inverse relationship between FA and disease severity, but not with age. CONCLUSIONS: Findings of MR imaging in OTCD are often normal in patients with late-onset disease, heterozygotes, or in those not in hyperammonemic crisis. DTI was more sensitive than FSE T2-weighted imaging for detecting abnormalities in normal-appearing white matter. The extent of abnormality correlated with cognitive deficits. The location of the deficits in the frontal white matter is important because this area connects fibers that are vital to executive function, attention, and working memory.
Assuntos
Encéfalo/patologia , Transtornos Cognitivos/complicações , Transtornos Cognitivos/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Fibras Nervosas Mielinizadas/patologia , Doença da Deficiência de Ornitina Carbomoiltransferase/patologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doença da Deficiência de Ornitina Carbomoiltransferase/complicações , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto JovemRESUMO
Holoprosencephaly (HPE), which results from failed or incomplete midline forebrain division early in gestation, is the most common forebrain malformation. The etiology of HPE is complex and multifactorial. To date, at least 12 HPE-associated genes have been identified, including TGIF (transforming growth factor beta-induced factor), located on chromosome 18p11.3. TGIF encodes a transcriptional repressor of retinoid responses involved in TGF-ß signaling regulation, including Nodal signaling. TGIF mutations are reported in approximately 1-2% of patients with non-syndromic, non-chromosomal HPE. We combined data from our comprehensive studies of HPE with a literature search for all individuals with HPE and evidence of mutations affecting TGIF in order to establish the genotypic and phenotypic range. We describe 2 groups of patients: 34 with intragenic mutations and 21 with deletions of TGIF. These individuals, which were ascertained from our research group, in collaboration with other centers, and through a literature search, include 38 probands and 17 mutation-positive relatives. The majority of intragenic mutations occur in the TGIF homeodomain. Patients with mutations affecting TGIFrecapitulate the entire phenotypic spectrum observed in non-chromosomal, non-syndromic HPE. We identified a statistically significant difference between the 2 groups with respect to inheritance, as TGIF deletions were more likely to be de novo in comparison to TGIF mutations (χ(2) ((2)) = 6.97, p(permutated) = 0.0356). In addition, patients with TGIF deletions were also found to more commonly present with manifestations beyond the craniofacial and neuroanatomical features associated with HPE (p = 0.0030). These findings highlight differences in patients with intragenic mutations versus deletions affecting TGIF, and draw attention to the homeodomain region, which appears to be particularly relevant to HPE. These results may be useful for genetic counseling of affected patients.
RESUMO
OBJECTIVE: To evaluate brain metabolism in subjects with partial ornithine transcarbamylase deficiency (OTCD) utilizing (1)H MRS. METHODS: Single-voxel (1)H MRS was performed on 25 medically-stable adults with partial OTCD, and 22 similarly aged controls. Metabolite concentrations from frontal and parietal white matter (FWM, PWM), frontal gray matter (FGM), posterior cingulate gray matter (PCGM), and thalamus (tha) were compared with controls and IQ, plasma ammonia, glutamine, and disease severity. RESULTS: Cases ranged from 19 to 59 years; average 34 years; controls ranged from 18 to 59 years; average 33 years. IQ scores were lower in cases (full scale 111 vs. 126; performance IQ 106 vs. 117). Decreased myoinositol (mI) in FWM (p=0.005), PWM (p<0.001), PCGM (p=0.003), and tha (p=0.004), identified subjects with OTCD, including asymptomatic heterozygotes. Glutamine (gln) was increased in FWM (p<0.001), PWM (p<0.001), FGM (p=0.002), and PCGM (p=0.001). Disease severity was inversely correlated with [mI] in PWM (r=-0.403; p=0.046) and directly correlated with [gln] in PCGM (r=0.548; p=0.005). N-Acetylaspartate (NAA) was elevated in PWM (p=0.002); choline was decreased in FWM (p=0.001) and tha (p=0.002). There was an inverse relationship between [mI] and [gln] in cases only. Total buffering capacity (measured by [mI/mI+gln] ratio, a measure of total osmolar capacity) was inversely correlated with disease severity in FWM (r=-0.479; p=0.018), PWM (r=-0.458; p=0.021), PCGM (r=-0.567; p=0.003), and tha (r=-0.345; p=0.037). CONCLUSION: Brain metabolism is impaired in partial OTCD. Depletion of mI and total buffering capacity are inversely correlated with disease severity, and serve as biomarkers.
Assuntos
Encéfalo/metabolismo , Imageamento por Ressonância Magnética/métodos , Doença da Deficiência de Ornitina Carbomoiltransferase/diagnóstico por imagem , Doença da Deficiência de Ornitina Carbomoiltransferase/metabolismo , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Estudos de Casos e Controles , Feminino , Humanos , Inositol/metabolismo , Masculino , Pessoa de Meia-Idade , Doença da Deficiência de Ornitina Carbomoiltransferase/diagnóstico , Radiografia , Índice de Gravidade de DoençaRESUMO
The urea cycle disorders constitute a group of rare congenital disorders caused by a deficiency of the enzymes or transport proteins required to remove ammonia from the body. Via a series of biochemical steps, nitrogen, the waste product of protein metabolism, is removed from the blood and converted into urea. A consequence of these disorders is hyperammonaemia, resulting in central nervous system dysfunction with mental status changes, brain oedema, seizures, coma, and potentially death. Both acute and chronic hyperammonaemia result in alterations of neurotransmitter systems. In acute hyperammonaemia, activation of the NMDA receptor leads to excitotoxic cell death, changes in energy metabolism and alterations in protein expression of the astrocyte that affect volume regulation and contribute to oedema. Neuropathological evaluation demonstrates alterations in the astrocyte morphology. Imaging studies, in particular (1)H MRS, can reveal markers of impaired metabolism such as elevations of glutamine and reduction of myoinositol. In contrast, chronic hyperammonaemia leads to adaptive responses in the NMDA receptor and impairments in the glutamate-nitric oxide-cGMP pathway, leading to alterations in cognition and learning. Therapy of acute hyperammonaemia has relied on ammonia-lowering agents but in recent years there has been considerable interest in neuroprotective strategies. Recent studies have suggested restoration of learning abilities by pharmacological manipulation of brain cGMP with phosphodiesterase inhibitors. Thus, both strategies are intriguing areas for potential investigation in human urea cycle disorders.
Assuntos
Amônia/metabolismo , Encéfalo/patologia , Enzimas/deficiência , Hiperamonemia/complicações , Hiperamonemia/diagnóstico , Erros Inatos do Metabolismo/complicações , Erros Inatos do Metabolismo/diagnóstico , Doenças do Sistema Nervoso/complicações , Doenças do Sistema Nervoso/diagnóstico , Ureia/metabolismo , Cognição , Enzimas/metabolismo , Feminino , Humanos , Hiperamonemia/terapia , Imageamento por Ressonância Magnética/métodos , Masculino , Erros Inatos do Metabolismo/terapia , Doenças do Sistema Nervoso/terapia , Nitrogênio/metabolismo , Resultado do TratamentoRESUMO
Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare autosomal recessive disorder affecting CNS gamma-aminobutyric acid (GABA) degradation. SSADH, in conjunction with GABA transaminase, converts GABA to succinate. In the absence of SSADH, GABA is converted to 4-OH-butyrate. The presence of 4-OH-butyrate, a highly volatile compound, may be undetected on routine organic acid analysis. Urine organic acid testing was modified at the authors' institution in 1999 to screen for the excretion of 4-OH-butyrate by selective ion monitoring gas chromatography-mass spectrometry in addition to total ion chromatography. Since then, five patients with 4-hydroxybutyric aciduria have been identified. The authors add the clinical, neuroimaging, and EEG findings from a new cohort of patients to 51 patients reported in the literature with clinical details. Ages ranged from 1 to 21 years at diagnosis. Clinical findings include mild-moderate mental retardation, disproportionate language dysfunction, hypotonia, hyporeflexia, autistic behaviors, seizures, and hallucinations. Brain MRI performed in five patients at the authors' institution revealed symmetric increased T2 signal in the globus pallidi. SSADH deficiency is an under-recognized, potentially manageable neurometabolic disorder. Urine organic acid analysis should include a sensitive method for the detection of 4-hydroxybutyrate and should be obtained from patients with mental retardation or neuropsychiatric disturbance of unknown etiology.
Assuntos
Aldeído Oxirredutases/deficiência , Hidroxibutiratos/urina , Adolescente , Adulto , Transtorno Autístico/etiologia , Criança , Pré-Escolar , Estudos de Coortes , Eletroencefalografia , Feminino , Genes Recessivos , Globo Pálido/patologia , Humanos , Lactente , Deficiência Intelectual/etiologia , Transtornos da Linguagem/etiologia , Imageamento por Ressonância Magnética , Masculino , Convulsões/etiologia , Succinato-Semialdeído Desidrogenase , Ácido gama-Aminobutírico/metabolismoRESUMO
We report the first frame-shift truncation mutation in a mitochondrial DNA (mtDNA)-encoded subunit II of cytochrome c oxidase (COXII). The mutation was identified by temporal temperature gradient gel electrophoresis (TTGE) followed by direct DNA sequencing in an infant who died at 12 days of age following a course of apnea, bradycardia, and severe lactic acidosis. The patient had a twin brother who died at two days of age of similar course. The mutation, 8042delAT, produced a truncated protein that was 72 amino acids shorter than the wild type protein. The mutant protein, missing one third of the amino acid residues at the C-terminal essential for hydrophilic interaction with cytochrome c, ligand binding to CuA and Mg, and the formation of proton and water channels, apparently has devastating effects on mitochondrial respiratory function.
Assuntos
Acidose Láctica/genética , DNA Mitocondrial/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Acidose Láctica/patologia , Sequência de Bases , Análise Mutacional de DNA , DNA Mitocondrial/química , Saúde da Família , Evolução Fatal , Feminino , Mutação da Fase de Leitura , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Masculino , LinhagemRESUMO
Aminoglycosides have previously been shown to suppress nonsense mutations, allowing translation of full-length proteins in vitro and in animal models. In the mdx mouse, where muscular dystrophy is due to a nonsense mutation in the dystrophin gene, gentamicin suppressed truncation of the protein and ameliorated the phenotype. A subset of patients with Duchenne and Becker muscular dystrophy similarly possess a nonsense mutation, causing premature termination of dystrophin translation. Four such patients, with various stop codon sequences, were treated once daily with intravenous gentamicin at 7.5 mg/kg/day for 2 weeks. No ototoxicity or nephrotoxicity was detected. Full-length dystrophin was not detected in pre- and post-treatment muscle biopsies.
Assuntos
Códon sem Sentido/genética , Gentamicinas/uso terapêutico , Distrofia Muscular de Duchenne/tratamento farmacológico , Distrofia Muscular de Duchenne/genética , Adolescente , Biópsia , Western Blotting , Criança , Creatina Quinase/sangue , Distrofina/biossíntese , Distrofina/química , Distrofina/genética , Distrofina/imunologia , Gentamicinas/administração & dosagem , Gentamicinas/efeitos adversos , Humanos , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiopatologia , Distrofia Muscular de Duchenne/sangue , Distrofia Muscular de Duchenne/metabolismo , Fenótipo , Resultado do TratamentoRESUMO
Mitochondrial cytopathies are caused by genetic alterations of nuclear- or mitochondrial-encoded genes involved in the synthesis of subunits of the electron transport chain. Mutations of mitochondrial DNA are associated with a wide range of clinical presentations [1-4]. The ubiquitous nature of mitochondria and the role of the mitochondria in cellular metabolism result in the potential for any tissue in the body to be affected [5-7,8..,9]. Although some children with mitochondrial disease present with life-threatening lactic acidosis in the newborn period, the majority of children come to clinical attention for nonspecific problems, including failure to thrive, developmental delay, seizures, hypotonia, and loss of developmental milestones. The diagnosis of these disorders is made through careful clinical evaluation, coupled with biochemical, morphologic, and molecular biologic techniques. Genetic counseling is difficult due to unique aspects of mitochondrial genetics. Despite advances in our understanding of mitochondrial biochemistry and genetics, treatment options remain limited.
Assuntos
Doenças Mitocondriais/diagnóstico , Biomarcadores , Biópsia , Criança , Pré-Escolar , Deficiência de Citocromo-c Oxidase , DNA/genética , Análise Mutacional de DNA , Replicação do DNA , DNA Mitocondrial/genética , Eletroencefalografia , Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Metabolismo Energético/genética , Aconselhamento Genético , Humanos , Lactente , Doença de Leigh/enzimologia , Doença de Leigh/genética , Síndrome MELAS/genética , Imageamento por Ressonância Magnética , Doenças Mitocondriais/classificação , Doenças Mitocondriais/dietoterapia , Doenças Mitocondriais/genética , Doenças Mitocondriais/metabolismo , Músculo Esquelético/patologia , Atrofia Óptica Hereditária de Leber/genética , Fosforilação Oxidativa , Mutação Puntual , Biossíntese de Proteínas , Deleção de Sequência , SíndromeRESUMO
The oculocerebrorenal syndrome of Lowe (OCRL) is an X-linked disorder characterized by congenital cataracts, mental retardation, and renal tubular dysfunction. The gene responsible for OCRL was identified by positional cloning and encodes a lipid phosphatase, phosphatidylinositol 4,5, bisphosphate [PtdIns(4,5)P2]5-phosphatase, which localizes to the Golgi apparatus and is suspected to play a role in Golgi vesicular transport [Suchy et al., 1995]. In addition to the ocular and renal manifestations, most boys with OCRL have cognitive problems and maladaptive behaviors including tantrums and stereotypies. We report a boy with a history of congenital cataracts and mild developmental delay who was also found to have hematuria with proteinuria but minimal signs of renal tubular dysfunction. Subsequent renal biopsy was compatible with a diagnosis of a noncomplement fixating chronic glomerulonephritis. Despite the atypical renal findings, skin fibroblast analysis for PtdIns (4,5)P2 5-phosphatase was performed, and enzyme activity was low, consistent with the diagnosis of OCRL. Western blot analysis from cell lysates showed the ocrl protein was decreased in size and amount. Our report shows atypical renal features of OCRL in a mildly affected boy. The possibility of OCRL should be considered in boys with cataracts and glomerular disease, even in the absence of renal tubular defects and frank mental retardation usually associated with the syndrome. Am. J. Med. Genet. 95:461-466, 2000. Published Wiley-Liss, Inc.