RESUMO
VRK1 encodes a serine/protein kinase possibly involved in pathways related to amyotrophic lateral sclerosis (ALS) pathogenesis. Pathogenic variants in VRK1 have been related to different phenotypes. We describe the clinical phenotype of two unrelated Portuguese patients with different VRK1 variants. Both patients presented a bilateral distal weakness in lower limbs beginning in childhood slowly progressing to upper limbs, associated with pyramidal signs, without bulbar, respiratory or cognitive involvement, according to probable ALS. Imaging and nerve conduction studies were unremarkable in both patients. Genetic testing in patient 1 identified two VRK1 variants in heterozygosity: c.265C > T, p.(Arg89*) and c.769G > A, p.(Gly257Ser), classified as pathogenic and variant of uncertain significance, respectively. In patient 2, two probably pathogenic variants in VRK1 were identified in heterozygosity: c.710-14T > C in intron 8 and c.721C > T, p.(Arg241Cys) in exon 9. We report two unrelated patients with different variants in VRK1 displaying a similar childhood-onset motor neuron disease/ALS, further expanding the phenotypic spectrum associated to VRK1 variants.
Assuntos
Variação Genética/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Doença dos Neurônios Motores/diagnóstico por imagem , Doença dos Neurônios Motores/genética , Proteínas Serina-Treonina Quinases/genética , Adulto , Idade de Início , Criança , Humanos , Masculino , Linhagem , PortugalRESUMO
Macrodactyly in the context of tuberous sclerosis complex (TSC) is a known but rare manifestation. We report the case of a boy diagnosed with TSC at 2 years and 4 months of age, presenting with bilateral macrodactyly of the first three fingers of both hands, with underlying radiographic changes, in whom molecular analysis identified a frameshift mutation on the TSC1 gene (encoding hamartin), leading to a premature stop codon. We reviewed the literature for reported cases of TSC patients with the same manifestation. In four of 14 patients, including ours, macrodactyly caused some type of joint limitation or flexion deformity, thus contradicting the established idea that this is a finding without clinical significance. Our patient is, to our knowledge, the first reported to have clear bilateral involvement. We briefly discuss the underlying mechanism for this phenomenon, which has yet to be fully elucidated, although somatic mosaicism for loss of heterozygosity at TSC loci is a plausible explanation. © 2016 Wiley Periodicals, Inc.
