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Browsing by Author "Sousa, AB"

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  • Adding Evidence to the Role of NEUROG1 in Congenital Cranial Dysinnervation Disorders
    Publication . Dupont, J; Vieira, JP; Tavares, AL; Conceição, C; Khan, S; Bertoli-Avella, AM; Sousa, AB
    Congenital cranial dysinnervation disorders (CCDDs) are a heterogeneous group of neurodevelopmental phenotypes caused by a primary disturbance of innervation due to deficient, absent, or misguided cranial nerves. Although some CCDDs genes are known, several clinical phenotypes and their aetiologies remain to be elucidated. We describe a 12-year-old boy with hypotonia, developmental delay, sensorineural hearing loss, and keratoconjunctivitis due to lack of corneal reflex. He had a long expressionless face, severe oromotor dysfunction, bilateral agenesis/severe hypoplasia of the VIII nerve with marked atresia of the internal auditory canals and cochlear labyrinth malformation. Trio-exome sequencing identified a homozygous loss of function variant in the NEUROG1 gene (NM_006161.2: c.202G > T, p.Glu68*). NEUROG1 is considered a causal candidate for CCDDs based on (i) the previous report of a patient with a homozygous gene deletion and developmental delay, deafness due to absent bilateral VIII nerves, and severe oromotor dysfunction; (ii) a second patient with a homozygous NEUROG1 missense variant and corneal opacity, absent corneal reflex and intellectual disability; and (iii) the knockout mouse model phenotype which highly resembles the disorder observed in humans. Our findings support the growing compelling evidence that loss of NEUROG1 leads to a very distinctive disorder of cranial nerves development.
    2021-04Journal article Open access Show more
  • Clinical and Molecular Characterization of Diastrophic Dysplasia in the Portuguese Population
    Publication . Barbosa, M; Sousa, AB; Medeira, A; Lourenço, T; Saraiva, J; Pinto-Basto, J; Soares, G; Fortuna, AM; Superti-Furga, A; Mittaz, L; Reis-Lima, M; Bonafé, L
    SLC26A2-related dysplasias encompass a spectrum of diseases: from lethal achondrogenesis type 1B (ACG1B; MIM #600972) and atelosteogenesis type 2 (AO2; MIM #256050) to classical diastrophic dysplasia (cDTD; MIM #222600) and recessive multiple epiphyseal dysplasia (rMED; MIM #226900). This study aimed at characterizing clinically, radiologically and molecularly 14 patients affected by non-lethal SLC26A2-related dysplasias and at evaluating genotype-phenotype correlation. Phenotypically, eight patients were classified as cDTD, four patients as rMED and two patients had an intermediate phenotype (mild DTD - mDTD, previously 'DTD variant'). The Arg279Trp mutation was present in all patients, either in homozygosity (resulting in rMED) or in compound heterozygosity with the known severe alleles Arg178Ter or Asn425Asp (resulting in DTD) or with the mutation c.727-1G>C (causing mDTD). The 'Finnish mutation', c.-26+2T>C, and the p.Cys653Ser, both frequent mutations in non-Portuguese populations, were not identified in any of the patients of our cohort and are probably very rare in the Portuguese population. A targeted mutation analysis for p.Arg279Trp and p.Arg178Ter in the Portuguese population allows the identification of approximately 90% of the pathogenic alleles.
    2011Journal article Open access Show more
  • New Ocular Findings in a Patient with a Novel Pathogenic Variant in the FBXO11 Gene
    Publication . Silva, RG; Dupont, J; Silva, E; Sousa, AB
    Intellectual developmental disorder with dysmorphic facies and behavioral abnormalities (IDDFBA) is a recently described autosomal dominant entity caused by pathogenic variants, mostly de novo, in the FBXO11 gene. It presents in the first years of life with highly variable clinical manifestations. The main features of IDDFBA include borderline-to-severe intellectual disability, behavioral problems, hypotonia, facial dysmorphisms, minor skeletal abnormalities, and recurrent infections. Although eye problems, such as refractive errors, eye misalignment and minor visual changes, have been described in about 48% of patients, a major ocular defect, namely, bilateral optic nerve hypoplasia, has been reported in the literature only once. We report an 8-year-old boy with a novel de novo pathogenic variant in FBXO11 gene (NM_001190274.1: c.1166dup, p.Cys390Metfs∗3) and a complex ophthalmological phenotype, consisting of right microphthalmia, very shallow anterior chamber, and persistent pupillary membrane, right dense nuclear cataract, bilateral optic nerve hypoplasia, and bilateral horizontal manifest nystagmus.
    2022Journal article Open access Show more