RESUMO
In a patient with CdLS (IV.16) we identifed a novel single basepair deletion (c.704delG) in RAD21, which encodes a cohesin pathway protein. The variant is predicted to result in a premature stop codon [p.(Ser235Ilefs*19)] and hereby would have a deleterious effect. RAD21 variants have previously been described only in five cases with cohesinopathies (b). Notably, the deletion was found in the mother and the two aunts of the index patient, and none of them had been suspected of having CdLS or a cohesinopathy prior to this study (a). The index patient can be classified as mild CdLS, but the other family members do not fulfill the diagnostic criteria of CdLS. This study together with previous reports suggests incomplete penetrance associated with RAD21 variants and these individuals may therefore be underdiagnosed.
Assuntos
Síndrome de Cornélia de Lange/diagnóstico , Síndrome de Cornélia de Lange/genética , Proteínas Nucleares/genética , Fosfoproteínas/genética , Deleção de Sequência/genética , Adulto , Proteínas de Ciclo Celular , Códon sem Sentido/genética , Proteínas de Ligação a DNA , Síndrome de Cornélia de Lange/fisiopatologia , Feminino , Humanos , Penetrância , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Cornelia de Lange syndrome (CdLS; MIM #122470, 300590, 610759, 614701, 300882) is a rare and clinically variable disorder that affects multiple organs. It is characterized by intellectual disability (mild to severe), distinctive facial features, prenatal and postnatal growth retardation, and hirsutism. Congenital anomalies include malformations of the upper limbs, gastrointestinal malformation/rotation, pyloric stenosis, diaphragmatic hernia, heart defects and genitourinary malformations. Gastroesophageal reflux disease is present in almost all patients. In addition to classic forms, milder phenotypes have been reported. To date five genes [NIPBL (Nipped-B-like protein), SMC1A (structural maintenance of chromosomes 1A), SMC3 (structural maintenance of chromosomes 3), RAD21 (human homolog of Schizosaccharomyces pombe radiation sensitive mutant 21) and HDAC8 (histone deacetylase 8)] have been associated with CdLS and mutations of these genes comprise the underlying defect in 70% of the patients. Here, we will provide a brief review of the clinical features of CdLS, summarize the known underlying genetic defects, prenatal and postnatal diagnosis possibilities, and genetic counseling.