RESUMO
El déficit hereditario de alfa 1-antitripsina ( 1-AT) predispone al desarrollo de enfisema pulmonar. Elobjetivo de este trabajo es evidenciar las limitaciones de algunos métodos de laboratorio utilizados en elestudio del déficit, cuya interpretación puede inducir a error en la detección de alelos poco frecuentes.Se describen dos casos clínicos: la paciente índice, que presentaba enfisema pulmonar con niveles de 1-AT inferiores a 12 mg/dL, catalogada erróneamente como homocigota de la variante alélica normalPI MM mediante un método de genotipificado rápido; la madre de la paciente, asintomática, con nivelesbajos (60 mg/dL), catalogada también como PI MM.La secuenciación del gen catalogó a la paciente índice como portadora del alelo nulo PI Clayton y deldeficitario PI Mmalton. La madre resultó portadora heterocigota PI Clayton/PI M.Los resultados ponen de relieve las dificultades de diagnóstico del déficit así como la necesidad deconsensuar métodos para este estudio(AU)
Hereditary alpha-1-antitrypsin ( 1-AT) deficiency predisposes to pulmonary emphysema. The objectiveof this study is to demonstrate the limitations of some laboratory methods used in the study of thedeficiency, and which may produce errors in interpretation and detection of uncommon alleles.Two clinical cases are described: the index patient, who had pulmonary emphysema with 1-AT levelsless than 12 mg/dL, was erroneously classified as a homozygote of the normal allelic variant PIMMusinga rapid genotype method; the mother of the patient, asymptomatic, with low levels (60 mg/dL), was alsoclassified as PI MM.The gene sequencing classified the index patient as a carrier of the PI Clayton null allele and PI Mmaltondeficient. The mother was a PI Clayton/PI heterozygote carrier.These results highlight the difficulties in diagnosing the deficiency, as the well as the need to reach aconsensus on methods for this study(AU)
Assuntos
Humanos , Deficiência de alfa 1-Antitripsina/diagnóstico , Enfisema Pulmonar/genética , Predisposição Genética para Doença , Alelos , Teste de Complementação GenéticaRESUMO
Hereditary alpha-1-antitrypsin (α1-AT) deficiency predisposes to pulmonary emphysema. The objective of this study is to demonstrate the limitations of some laboratory methods used in the study of the deficiency, and which may produce errors in interpretation and detection of uncommon alleles. Two clinical cases are described: the index patient, who had pulmonary emphysema with α1-AT levels less than 12 mg/dL, was erroneously classified as a homozygote of the normal allelic variant PI MM using a rapid genotype method; the mother of the patient, asymptomatic, with low levels (60 mg/dL), was also classified as PI MM. The gene sequencing classified the index patient as a carrier of the PI Clayton null allele and PI Mmalton deficient. The mother was a PI Clayton/PI heterozygote carrier. These results highlight the difficulties in diagnosing the deficiency, as the well as the need to reach a consensus on methods for this study.
