Cap a la genètica assistencial interdisciplinària i transversal: evolució de cinquanta anys en un hospital terciari a partir de la pediatria / Hacia la genètica asistencial interdisciplinaria y transversal: evolución de cincuenta años en un hospital terciario a partir de la pediatría / Towards interdisciplinary and transversal clinical genetics: a 50-year evolution from pediatrics in a tertiary hospital

L’objectiu d’aquest treball és analitzar l’evolució de la demanda assistencial i les possibilitats diagnòstiques, en laconsulta de genètica clínica d’un hospital de tercer nivell durant els últims cinquanta anys i també a partir dels seus inicis com a consulta específica de Pediatria.S’hi analitzen tant els motius de consulta com les proves de laboratori disponibles per arribar al diagnòstic dels pacients valorats durant el període 1968-2018, a la consulta de Genètica Clínica i al Laboratori de Genètica. A partir de 200 consultes anuals, en els primers anys, arribem a l’actualitat, en què se’n fan al voltant de 8.000 (entre primeres, successives i interconsultes), distribuïdes en Genètica Clínica i Assessorament Genètic, fins a un total de més de 32.000 pacients visitats durant aquests cinquanta anys.Al Laboratori de Genètica, l’evolució abasta des de l’estudi del cariotip convencional fins a l’aplicació de les tecnologies genòmiques actuals, i s’hi fan més de 9.000 estudis anuals de pacients de l’Hospital. Amb la incorporació de noves tecnologies moleculars s’ha canviat el paradigma de l’estudi genètic i s’ha aconseguit un rendiment millor: s’han pogut incrementar els diagnòstics i també s’ha reduït el temps necessari per obtenir-los.A més de la transformació del genetista que col·labora en el seguiment multidisciplinari dels pacients, s’evidencia uncanvi i una diversificació del motiu de consulta i s’estableix el valor de la incorporació, a partir del 2010, de professionals especialitzats en assessorament genètic per donar resposta a aquesta demanda.Els canvis experimentats en els motius de consulta, els diagnòstics i les proves de laboratori fetes durant tots aquests anys reflecteixen la importància de la incorporació i la interacció, en una mateixa àrea o unitat assistencial, de professionals especialitzats en genètica clínica, assessorament genètic i laboratori de genètica integral (també ambbioinformàtics). (AU)

El objetivo de este trabajo es analizar la evolución de la demandaasistencial y las posibilidades diagnósticas en la consulta de genética clínica de un hospital de tercer nivel a lo largo de los últimos50 años a partir de sus inicios como una consulta específica dePediatría.Se analizan los motivos de consulta y las pruebas de laboratorio disponibles para llegar al diagnóstico de los pacientes valorados en el período 1968-2018 en la Consulta de Genética Clínica y el Laboratorio de Genética. A partir de 200 consultas anuales en los primeros años llegamos a la actualidad, en que se realizan alrededor de 8.000 visitas (primeras, sucesivas e interconsultas) distribuidas en Genética Clínica y Asesoramiento Genético (32.000pacientes visitados hasta la fecha).En el laboratorio de Genética la evolución abarca desde el estudio del cariotipo convencional hasta la aplicación de las tecnologías genómicas actuales realizando más de 9.000 estudios anuales de pacientes del Hospital. Además de la transformación del genetista clínico colaborando en el seguimiento multidisciplinar de los pacientes, se evidencia un cambio y diversificación del motivo de consulta y se establece el valor de la incorporación de profesionales especializados en asesoramiento genético (a partir de 2010) para dar respuesta a esta demanda. Con la incorporación de nuevas tecnologías moleculares se ha cambiado el paradigma del estudio genético con un incremento importante del rendimiento y mejoría en el tiempo en obtener resultados diagnósticos. Los cambios experimentados en los motivos de consulta, los diagnósticos y las pruebas de laboratorio realizadas a lo largo de estos años reflejan la importancia de la incorporación e interacción, en una misma área/unidad asistencial, de profesionales especializados en genética clínica, asesores genéticos y laboratorio de genética integral (incluyendo bioinformáticos). (AU)

The objective of this work is to analyze the evolution of the demand and the diagnostic capabilities in the clinical genetics service of a tertiary hospital over the last 50 years from its initiationas a specific pediatric consultation. The reasons for consultationare analyzed as well as the laboratory tests available to reach thediagnosis of the patients evaluated in the period 1968-2018 at the Clinical Genetics Service and the Genetics Laboratory. From 200 consultations/year in the first years, we have reachedaround 8,000 visits (first, follow-up, and internal consultations) distributed in Clinical Genetics and Genetic Counseling (32,000patients visited to date).The Genetics Laboratory evolved from the study of the conventional karyotype to the application of state of the art genomic technologies, carrying out more than 9,000 annual studies from patients followed–up in the hospital.In addition to the transformation of the role of the clinical geneticist into a member of the multidisciplinary care team, there isevidence of a change and diversification of the reasons for consultation and in the value of incorporating professionals specializedin genetic counseling (starting in 2010) to respond to this demand. With the incorporation of new molecular technologies, theparadigm of the genetic study has changed, with a significant increase in performance and improving time to diagnostic results.The changes experienced in the reasons for consultation, diagnosesand laboratory tests carried out throughout these years reflect theimportance of the incorporation and interaction, in the same healthcare area or unit, of professionals specialized in clinical geneticsand genetic counseling, with a comprehensive genetics laboratory(including bioinformatics). (AU)

Clinical utility of chromosomal microarray analysis in invasive prenatal diagnosis.

Novel methodologies for detection of chromosomal abnormalities have been made available in the recent years but their clinical utility in prenatal settings is still unknown. We have conducted a comparative study of currently available methodologies for detection of chromosomal abnormalities after invasive prenatal sampling.A multicentric collection of a 1-year series of fetal samples with indication for prenatal invasive sampling was simultaneously evaluated using three screening methodologies: (1) karyotype and quantitative fluorescent polymerase chain reaction (QF-PCR), (2) two panels of multiplex ligation-dependent probe amplification (MLPA), and (3) chromosomal microarray-based analysis (CMA) with a targeted BAC microarray. A total of 900 pregnant women provided informed consent to participate (94% acceptance rate). Technical performance was excellent for karyotype, QF-PCR, and CMA (~1% failure rate), but relatively poor for MLPA (10% failure). Mean turn-around time (TAT) was 7 days for CMA or MLPA, 25 for karyotype, and two for QF-PCR, with similar combined costs for the different approaches. A total of 57 clinically significant chromosomal aberrations were found (6.3%), with CMA yielding the highest detection rate (32% above other methods). The identification of variants of uncertain clinical significance by CMA (17, 1.9%) tripled that of karyotype and MLPA, but most alterations could be classified as likely benign after proving they all were inherited. High acceptability, significantly higher detection rate and lower TAT, could justify the higher cost of CMA and favor targeted CMA as the best method for detection of chromosomal abnormalities in at-risk pregnancies after invasive prenatal sampling.

Increased MLL gene rearrangements in amniocytes from fetuses of mothers who smoke.

We assess the possible genotoxic effect of maternal smoking on amniotic fluid cells, based on the presence of an increasing of structural abnormality of the 11q23 band bearing the MLL gene rearrangements. In this observational and prospective study cultured amniocytes were obtained from 20 control and 20 women who smoke (>10 cigarettes/day for >10 years and during pregnancy). We performed fluorescence in situ hybridization (FISH) analysis in amniocytes. Comparison of FISH data between smoker and control groups showed statistical significance for the MLL gene rearrangements. Epidemiologic studies, including a large series of patients, will be needed to determine whether the offspring of parents who smoke have an increased lifetime risk of leukemia.

Assessment of QF-PCR as the first approach in prenatal diagnosis.

Quantitative fluorescent PCR (QF-PCR) has been used by many laboratories for prenatal diagnosis of the most common aneuploidies. QF-PCR is rapid, cost-effective, and suitable for automation and can detect most abnormalities diagnosed by conventional karyotyping. Whether QF-PCR should be used alone in most of the samples and in which karyotyping should also be offered is currently a topic of debate. We evaluated and compared the results obtained from 7679 prenatal samples in which conventional karyotype and QF-PCR had been performed, including 1243 chorionic villi and 6436 amniotic fluid samples. Concordant QF-PCR and karyotype results were obtained in 98.75% of the samples. An abnormal karyotype associated with adverse clinical outcome undetected by QF-PCR was found in 0.05% of samples. Therefore, QF-PCR can be used alone in a large number of samples studied in a prenatal laboratory, thereby reducing both the workload in cytogenetic laboratories and parental anxiety when awaiting results.

A novel de novo BRCA2 mutation of paternal origin identified in a Spanish woman with early onset bilateral breast cancer.

Germ line mutations in either of the two major breast cancer predisposition genes, BRCA1 and BRCA2, account for a significant proportion of hereditary breast/ovarian cancer. Identification of breast cancer patients carrying mutations in any of these genes is primarily based on a positive family history of breast/ovarian cancer or early onset of the disease. In the course of mutation screening of the BRCA1 and BRCA2 genes in a hospital based series of patients with risk factors for hereditary breast/ovarian cancer, we identified a novel germ line mutation in the BRCA2 gene (c.51dupA) in a patient with early onset bilateral breast cancer and no family history of the disease. None of her parents carried the mutation, and paternity was confirmed. Subsequent molecular analysis demonstrated that the mutation was a novel de novo germ line mutation located in the paternal allele of the BRCA2 gene.

Rapid prenatal diagnosis of aneuploidies and zygosity in multiple pregnancies by amniocentesis with single insertion of the needle and quantitative fluorescent PCR.

OBJECTIVE: To investigate amniotic fluid (AF) samples retrieved in multiple pregnancies by single insertion of the needle, for rapid assessment of chromosome copy number, zygosity, and cross-contamination between fetuses, using Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) amplification of highly polymorphic microsatellite markers. METHODS: Fifty-two multiple pregnancies were selected (47 twins, 5 triplets) and 108 samples of amniotic fluid were sampled between 12 to 20 weeks of gestation (mean 15.5) using the single-needle technique. Aneuploidy screening by QF-PCR amplification of short tandem repeats (STRs) on chromosomes X, Y, 21, 13, and 18 was carried out within 24 h of collection. Owing to the sampling procedure, the eventual presence of contamination between fetuses was also evaluated in every case. RESULTS: Normal and aneuploid fetuses were readily identified by QF-PCR. Fetal reduction was made available, for trisomic fetuses, without further waiting for completion of fetal karyotyping. In twin gestations, the ultrasound examination of chorionicity was always in agreement with the molecular assessment of zygosity. Contamination between fetuses due to the sampling procedure with a single puncture was never observed. CONCLUSION: Rapid prenatal diagnosis of aneuploidies by QF-PCR is a sensitive, efficient, and reliable assay. When applied in multiple pregnancies, it has the added value of allowing the assessment of zygosity in all cases, independently of chorionicity and fetal sex.