Rescuing monopronucleated-derived human blastocysts: a model to study chromosomal topography and fingerprinting.

OBJECTIVE: To quantify the percentage of monopronuclear-derived blastocysts (MNBs) that are potentially useful for reproductive purposes using classic and state-of-the-art chromosome analysis approaches, and to study chromosomal distribution in the inner cell mass (ICM) and trophectoderm (TE) for intertissue/intratissue concordance comparison. DESIGN: Prospective experimental study. SETTING: Single-center in vitro fertilization clinic and reproductive genetics laboratory. PATIENT(S): A total of 1,128 monopronuclear zygotes were obtained between June 2016 and December 2018. INTERVENTION(S): MNBs were whole-fixed or biopsied to obtain a portion of ICM and 2 TE portions (TE1 and TE2) and were subsequently analyzed by fluorescence in situ hybridization, new whole-genome sequencing, and fingerprinting by single-nucleotide polymorphism array-based techniques (a-SNP). MAIN OUTCOME MEASURE(S): We assessed MNB rate, ploidy rate, and chromosomal constitution by new whole-genome sequencing, and parental composition by comparative a-SNP, performed in a "trio"-format (embryo/parents). The 24-chromosome distribution was compared between the TE and the ICM and within the TE. RESULT(S): A total of 18.4% of monopronuclear zygotes progressed to blastocysts; 77.6% of MNBs were diploid; 20% of MNBs were male and euploid, which might be reproductively useful. Seventy-five percent of MNBs were biparental and half of them were euploid, indicating that 40% might be reproductively useful. Intratissue concordance (TE1/TE2) was established for 93.3% and 73.3% for chromosome matching. Intertissue concordance (TE/ICM) was established for 78.8%, but 57.6% for chromosome matching. When segmental aneuploidy was not considered, intratissue concordance and chromosome matching increased to 100% and 80%, respectively, and intertissue concordance and chromosome matching increased to 84.8% and 75.8%, respectively. CONCLUSION(S): The a-SNP-trio strategy provides information about ploidy, euploidy, and parental origin in a single biopsy. This approach enabled us to identify 40% of MNBs with reproductive potential, which can have a significant effect in the clinical setting. Additionally, segmental aneuploidy is relevant for mismatched preimplantation genetic testing of aneuploidies, both within and between MNB tissues. Repeat biopsy might clarify whether segmental aneuploidy is a prone genetic character.

Hallazgo casual mediante array de polimorfismo de nucleótido simple. Síndrome de Warkany / Casual finding using single nucleotide polymorphisms arrays: warkany syndrome

Introducción: La trisomía del cromosoma 8, conocida como síndrome de Warkany, es una rara enfermedad genética que cursa con un fenotipo muy variable. Su principal característica clínica es la discapacidad intelectual, facies dismórficas y pliegues plantares profundos. Presentamos el caso de un paciente de 10 años de edad, con facies gargoloides, retraso mental y rigidez en las articulaciones. El estudio inicial del cariotipo, en el que se analizaron 20 metafases, fue normal. Se solicitó array de polimorfismos de nucleótido único (SNPs) al laboratorio. Resultados: Se detectó una ganancia completa del cromosoma 8, que se interpretó como una trisomía 8 en mosaico de aproximadamente un 20%, y que era compatible con la clínica que presentaba el paciente. Discusión: Este caso muestra las limitaciones que tiene el análisis de solo 20 metafases en el cariotipo en pacientes con aneuploidías en mosaico. En estos casos estaría recomendado ampliar el estudio a al menos 30 metafases de cara a detectar mosaicismos en baja proporción

Introduction: Chromosome 8 trisomy, known as Warkany syndrome, is a rare genetic disease that has a very variable phenotype. Its main clinical characteristic is intellectual disability, dysmorphic facies, and deep plantar folds. The case is presented of a 10-year-old patient with gargoyle-like facies, mental retardation, and joint stiffness. The initial study of the karyotype, in which 20 metaphases were analysed, was normal. A single nucleotide polymorphisms (SNPs) array was requested from the laboratory. Results: A complete gain of chromosome 8 was detected, which was interpreted as a mosaic trisomy 8 of approximately 20%, and which was compatible with the clinical presentation of the patient. Discussion: This case shows the limitations of the analysis of only 20 metaphases in the karyotype in patients with mosaic aneuploidies. In these cases it would be recommended to extend the study to at least 30 metaphases in order to detect mosaicisms in low proportion

Further Clinical and Molecular Delineation of Xp11.22 Deletion Syndrome: A Case Report.

Intellectual disability (ID) is the most common diagnosis noted among children with genetic disorders. It causes social and economic burden to families and communities. The genetic causes are not completely understood, and there is significant heterogeneity. Recently, a new chromosomal X-linked syndrome was reported to cause ID. Four males were described from three families with ID, developmental delay, hypotonia, joint hypermobility, and relative macrocephaly. They all carried small, overlapping Xp11.22 deletions. To date, the described smallest region of overlapping deletion at this locus spanned ~ 430 kb) and included four genes (CENPVL1, CENPVL2, MAGED1, and GSPT2), which are proposed as the main drivers of the phenotype. We describe a male patient who matches the phenotype and contributes to defining a narrow phenocritical region at Xp11.22. We propose that GSPT2 loss-of-function might be the probable cause of the phenotypic features seen in these patients.

Within-subject biological variation in disease: collated data and clinical consequences.

Quantitative data on the components of biological variation (BV) are used for several purposes, including calculating the reference change value (RCV) required for the assessment of the significance of changes in serial results in an individual. Pathology may modify the set point in diseased patients and, more importantly, the variation around that set-point. Our aim was to collate all published BV data in situations other than health. We report the within-subject coefficient of variation (CV(I)) for 66 quantities in 34 disease states. We compared the results with the CV(I) determined in healthy individuals and examined whether the data derived in specific diseases could be useful for clinical applications. For the majority of quantities studied, CV(I) values are of the same order in disease and health: thus the use of RCV derived from healthy subjects for monitoring patients would be reasonable. However, for a small number of quantities considered to be disease specific markers, the CV(I) differed from those in health. This could mean that RCV derived from healthy CV(I) may be inappropriate for monitoring patients in certain diseases. Hence, disease-specific RCVs may be clinically useful.