Analysis of Highly Conserved Regions of the 3'UTR of MECP2 Gene in Patients with Clinical Diagnosis of Rett Syndrome and Other Disorders Associated with Mental Retardation

In this work we explored the role of the 3'UTR of the MECP2 gene in patients with clinical diagnosis of RTT and mental retardation; focusing on regions of the 3'UTR with almost 100% conservation at the nucleotide level among mouse and human. By mutation scanning (DOVAM-S technique) the MECP2 3'UTR of a total of 66 affected females were studied. Five3'UTR variants in the MECP2 were found (c.1461+9G>A, c.1461+98insA, c.2595G>A, c.9961C>G and c.9964delC) in our group of patients. None of the variants found is located in putative protein-binding sites nor predicted to have a pathogenic role. Our data suggest that mutations in this region do not account for a large proportion of the RTT cases without a genetic explanation.

Genetic Screening of LCA in Belgium: Predominance of CEP290 and Identification of Potential Modifier Alleles in AHI1 of CEP290-Related Phenotypes

Leber Congenital Amaurosis (LCA), the most severe inherited retinal dystrophy, is genetically heterogeneous, with 14 genes accounting for 70% of patients. Here, 91 LCA probands underwent LCA chip analysis and subsequent sequencing of 6 genes (CEP290, CRB1, RPE65, GUCY2D, AIPL1and CRX), revealing mutations in 69% of the cohort, with major involvement of CEP290 (30%). In addition, 11 patients with early-onset retinal dystrophy (EORD) and 13 patients with Senior-Loken syndrome (SLS), LCA-Joubert syndrome (LCA-JS) or cerebello-oculo-renal syndrome (CORS) were included. Exhaustive re-inspection of the overall phenotypes in our LCA cohort revealed novel insights mainly regarding the CEP290-related phenotype. The AHI1 gene was screened as a candidate modifier gene in three patients with the same CEP290 genotype but different neurological involvement. Interestingly, a heterozygous novel AHI1 mutation, p.Asn811Lys, was found in the most severely affected patient. Moreover, AHI1 screening in five other patients with CEP290-related disease and neurological involvement revealed a second novel missense variant, p.His758Pro, in one LCA patient with mild mental retardation and autism. These two AHI1 mutations might thus represent neurological modifiers of CEP290-related disease.

Deficiência Mental: Casuística da Unidade de Desenvolvimento do Hospital de Dona Estefânia

Segundo a DSM IV a Deficiência Mental (DM) define-se como o funcionamento intelectual global inferior à média (QI < 70) associado a perturbações do comportamento adaptativo com início antes dos 18 anos. Procurou-se caracterizar retrospectivamente a população de crianças com DM observadas no Centro de Desenvolvimento do Hospital de Dona Estefânia (CDHDE), entre Janeiro 2005 e Junho 2007. Foram avaliados os dados epidemiológicos, gravidade, etiologia, co-morbilidade e intervenção proposta. Do total de 232 processos clínicos observados, 185 apresentavam DM. Classificaram-se em DM ligeira 112 (61%), DM moderada 54 (29%), DM grave 17 (9%) e profunda 2 (1%). Foram definidas etiologias em 86 crianças (46%) sendo a taxa de diagnóstico mais elevada na DM de maior gravidade. Observou-se uma elevada variabilidade de etiologias: as mais frequentemente encontradas foram as doenças genéticas, prematuridade e patologia associada. Foi detectada co-morbilidade em 123 crianças (66%), sendo a mais frequente as do foro oftalmológico (57 crianças, 46%). Foram propostas e sinalizadas para apoio a totalidade das crianças com DM, 47% em intervenção precoce e 58% em educação especial, das quais 5% usufruiram, por curto período, do apoio simultaneo de educadora de Intervenção Precoce e de docente do Ensino Especial, durante o período inicial de integração em jardim de infância. Observou-se um predomínio do sexo masculino. Foi efectuada caracterização clínica e funcional das crianças seguidas no CDHDE com o diagnóstico de DM e encontraram-se semelhanças entre os dados presentes e os descritos na literatura. Contudo alguns dados diferem de outras casuísticas decorrente, muito provavelmente decorrente da heterogeneidade da população estudada, quer do ponto de vista etiológico, quer no referente aos grupos etários, provavelmente condicionada, pela política assistencial.

Mutations in the MECP2 Gene Are Not a Major Cause of Rett Syndrome-Like or Related Neurodevelopmental Phenotype in Male Patients

Rett syndrome is a genetic neurodevelopmental disorder that affects mainly girls, but mutations in the causative MECP2 gene have also been identified in boys with classic Rett syndrome and Rett syndrome-like phenotypes. We have studied a group of 28 boys with a neurodevelopmental disorder, 13 of which with a Rett syndrome-like phenotype; the patients had diverse clinical presentations that included perturbations of the autistic spectrum, microcephaly, mental retardation, manual stereotypies, and epilepsy. We analyzed the complete coding region of the MECP2 gene, including the detection of large rearrangements, and we did not detect any pathogenic mutations in the MECP2 gene in these patients, in whom the genetic basis of disease remained unidentified. Thus, additional genes should be screened in this group of patients.

Non-Progressive Leukoencephalopathy with Bilateral Temporal Cysts

We report two cases of a peculiar leukoencephalopathy with temporal cysts. Both patients have a non-progressive neurological disorder with mental retardation, microcephaly and sensorineural deafness although clinical differences between them may reflect a different aetiology. The metabolic disorders with white matter involvement and the recently described leukoencephalopathies (Van Der Knaap disease, 'vanishing white matter disease') were excluded based on clinical, biologic and imaging findings. Cytomegalovirus infection is a likely possibility in the first case although the magnetic resonance imaging picture is only partially similar to previously reported cases. Our patients are strikingly similar to the patients reported by Deonna et al. and Olivier et al. We discuss the clinical and imaging findings in our patients and the differential diagnosis considering the known disorders of the white matter in childhood.

Primary Immunodeficiency Associated with Chromosomal Aberration - an ESID Survey

Patients with syndromic features frequently suffer from recurrent respiratory infections, but little is known about the spectrum of immunological abnormalities associated with their underlying chromosomal aberrations outside the well-known examples of Down and DiGeorge syndromes. Therefore, we performed this retrospective, observational survey study.