Miopatia Miotubular Ligada ao Cromossoma X - Caso Clínico

Introdução:A miopatia miotubular ligada ao cromossoma X e uma miopatia congénita grave neonatal que afecta o sexo masculino, com prognóstico reservado. Relato de Caso: Lactente com hipotonia generalizada grave detectada após o nascimento, atrofia muscular generalizada e abolição dos reflexos osteotendinosos, cujo estudo etiológico específico (biópsia muscular e estudo de genética molecular) revelo tratar-se de miopatia miotubular ligada ao cromossoma X. Internado em Unidade de Cuidados Intensivos até aos oito meses, foi submetido a traqueostomia e gastrotomia, tendo alta para domicílio. Faleceu aos dez meses, subitamente, de causa indeterminada. Discussão: Este caso mostra que, apesar da terapêutica actual ser apenas paliativa, a importância do conhecimento do mecanismo genético é enorme, abrindo novos horizontes para uma terapia génica no futuro.

Encefalite Crónica a Enterovírus num Doente com Agamaglobulinémia Congénita Ligada ao Cromossoma X

Os autores apresentam um caso clínico de encefalite crónica a enterovírus num rapaz de 9 anos com agamaglobulinémia congénita ligada ao cromossoma X (doença de Bruton). Apesar da terapêutica intraventricular com doses elevadas de gamaglobulina, registou-se uma progressão da doença com deterioração neurológica maciça e morte. Discutem-se os aspectos diagnósticos e terapêuticos desta situação.

Incontinentia Pigmenti in the Neonatal Period

Incontinentia pigmenti (IP) is a rare multisystem disease, X linked dominant disorder. As all X linked dominant diseases, it is usually male-lethal. Female newborn admitted to the neonatal intensive care unit on the fi rst day of life was diagnosed as having probable herpetic infection with vesicular skin lesions distributed on upper right limb and inferior limbs. Family history showed that her 22-year-old mother had hypopigmented lesions on the lower limbs and her 13-month-old sister had hyperpigmented lesions on the trunk and limbs. In newborns, herpes infection emerges as the principal diagnosis of vesicular rash, due to the importance of precocious diagnosis and treatment. Other hypothesis must be considered in a newborn with vesicobullous rash, such as IP.

Successful Handling of Disseminated BCG Disease in a Child with Severe Combined Immunodeficiency

In high-burden countries, Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccine is administered in newborn to prevent severe Mycobacterium tuberculosis infection. Because life-threatening disseminated BCG disease may occur in children with primary immunodeficiency, vaccination strategy against tuberculosis should be redefined in non-high-burden countries. We report the case of a patient with X-linked severe combined immunodeficiency (SCID) who developed disseminated BCG disease, highlighting the specific strategies adopted.

Undetectable Levels of CSF Amyloid-β Peptide in a Patient with 17β-Hydroxysteroid Dehydrogenase Deficiency

17β-hydroxysteroid dehydrogenase 10 (HSD10) deficiency is a rare X-linked inborn error of isoleucine catabolism. Although this protein has been genetically implicated in Alzheimer's disease pathogenesis, studies of amyloid-β peptide (Aβ) in patients with HSD10 deficiency have not been previously reported. We found, in a severely affected child with HSD10 deficiency, undetectable levels of Aβ in the cerebrospinal fluid, together with low expression of brain-derived neurotrophic factor, α-synuclein, and serotonin metabolites. Confirmation of these findings in other patients would help elucidating mechanisms of synaptic dysfunction in this disease, and highlight the role of Aβ in both early and late periods of life.

Giant Pericardial Cyst Mimicking Dextrocardia on Chest X-Ray

Pericardial cysts are rare benign congenital malformations, usually small, asymptomatic and detected incidentally on chest X-ray as a mass located in the right costophrenic angle. Giant pericardial cysts are very uncommon and produce symptoms by compressing adjacent structures. In this report, the authors present a case of a symptomatic giant pericardial cyst incorrectly diagnosed as dextrocardia on chest X-ray.

Acquired-Transient Factor X Deficiency in a Teenager with Extensive Burns

Acquired factor X deficiency is an extremely rare situation. It has shown to be associated with systemic amyloidosis, respiratory mycoplasma infection, factor X inhibitors, antiphospholipid antibodies, vitamin K defi ciency/liver disease as well as the use of certain medications (meropenem, valproic acid). The pathogenesis and transient nature of this deficit remain poorly understood. The authors describe the case of a teenager hospitalised for extensive burns that developed active bleeding after removal of central venous catheter. He was diagnosed with transient factor X deficiency. Normalisation of coagulation status and factor X levels occurred spontaneously 10 days after the bleeding episode.

A Novel Autosomal Recessive GJA1 Missense Mutation Linked to Craniometaphyseal Dysplasia

Craniometaphyseal dysplasia (CMD) is a rare sclerosing skeletal disorder with progressive hyperostosis of craniofacial bones. CMD can be inherited in an autosomal dominant (AD) trait or occur after de novo mutations in the pyrophosphate transporter ANKH. Although the autosomal recessive (AR)form of CMD had been mapped to 6q21-22 the mutation has been elusive. In this study, we performed whole-exome sequencing for one subject with AR CMD and identified a novel missense mutation (c.716G>A, p.Arg239Gln) in the C-terminus of the gap junction protein alpha-1 (GJA1) coding for connexin 43 (Cx43). We confirmed this mutation in 6 individuals from 3 additional families. The homozygous mutation cosegregated only with affected family members. Connexin 43 is a major component of gap junctions in osteoblasts, osteocytes, osteoclasts and chondrocytes. Gap junctions are responsible for the diffusion of low molecular weight molecules between cells. Mutations in Cx43 cause several dominant and recessive disorders involving developmental abnormalities of bone such as dominant and recessive oculodentodigital dysplasia (ODDD; MIM #164200, 257850) and isolated syndactyly type III (MIM #186100), the characteristic digital anomaly in ODDD. However, characteristic ocular and dental features of ODDD as well as syndactyly are absent in patients with the recessive Arg239Gln Cx43 mutation. Bone remodeling mechanisms disrupted by this novel Cx43 mutation remain to be elucidated.

Variant Rett Syndrome in a Girl with a Pericentric X-Chromosome Inversion Leading to Epigenetic Changes and Overexpression of the MECP2 Gene

Rett syndrome is a neurodevelopmental disorder caused by mutations in the MECP2 gene. We investigated the genetic basis of disease in a female patient with a Rett-like clinical. Karyotype analysis revealed a pericentric inversion in the X chromosome -46,X,inv(X)(p22.1q28), with breakpoints in the cytobands where the MECP2 and CDKL5 genes are located. FISH analysis revealed that the MECP2 gene is not dislocated by the inversion. However, and in spite of a balanced pattern of X inactivation, this patient displayed hypomethylation and an overexpression of the MECP2 gene at the mRNA level in the lymphocytes (mean fold change: 2.55±0.38) in comparison to a group of control individuals; the expression of the CDKL5 gene was similar to that of controls (mean fold change: 0.98±0.10). No gains or losses were detected in the breakpoint regions encompassing known or suspected transcription regulatory elements. We propose that the de-regulation of MECP2 expression in this patient may be due to alterations in long-range genomic interactions caused by the inversion and hypothesize that this type of epigenetic de-regulation of the MECP2 may be present in other RTT-like patients.