RESUMO
Snyder-Robinson syndrome (SRS, OMIM 309583) is a rare X-linked syndrome characterized by mental retardation, marfanoid habitus, skeletal defects, osteoporosis, and facial asymmetry. Linkage analysis localized the related gene to Xp21.3-p22.12, and a G-to-A transition at point +5 of intron 4 of the spermine synthase gene, which caused truncation of the SMS protein and loss of enzyme activity, was identified in the original family. Here we describe another family with Snyder-Robinson syndrome in two Mexican brothers and a novel mutation (c.496T>G) in the exon 5 of the SMS gene confirming its involvement in this rare X-linked mental retardation syndrome.
Assuntos
Cromossomos Humanos X , Genes Ligados ao Cromossomo X , Deficiência Intelectual Ligada ao Cromossomo X/genética , Mutação de Sentido Incorreto , Espermina Sintase/genética , Adulto , Análise Mutacional de DNA , Éxons , Ligação Genética , Humanos , Deficiência Intelectual/genética , Masculino , Síndrome de Marfan/genética , Osteoporose/genética , Linhagem , Escoliose/genética , Irmãos , Adulto JovemRESUMO
Mesomelic dysplasias (MD) are a group of skeletal disorders with exclusive or predominant shortness of the middle segment of the limbs, with or without involvement of the hands/feet or other body parts. Short stature is a usual consequence due to involvement of the lower limbs. In 2003, Camera and Camera reported an unusual upper limb MD with normal stature and radiological evidence of long bone metaphyseal dysplasia. Here, we describe a Mexican patient showing a similar clinical and radiological phenotype, in addition to esophageal atresia, palpebral ptosis and slight lower limb asymmetry. This represents the second case reported in the literature, corroborating the existence of this rare entity.