Genetics and human conception: DNA-based X-enriched sperm separation as an adjunct to preimplantation genetic testing for the prevention of X-linked disease

Introduction: Preimplantation genetic diagnosis and screening (PGD/PGS) has been applied clinically for >25 years however inherent drawbacks include the necessity to tailor each case to the trait in question, and that technology to detect monogenic and chromosomal disorders respectively is fundamentally different.Areas Covered: The area of preimplantation genetics has evolved over the last 25 years, adapting to changes in technology and the need for more efficient, streamlined diagnoses. Karyomapping allows the determination of inheritance from the (grand)parental haplobocks through assembly of inherited chromosomal segments. The output displays homologous chromosomes, crossovers and the genetic status of the embryos by linkage comparison, as well as chromosomal disorders. It also allows for determination of heterozygous SNP calls, avoiding the risks of allele dropout, a common problem with other PGD techniques. Manuscripts documenting the evolution of preimplantation genetics, especially those investigating technologies that would simultaneously detect monogenic and chromosomal disorders, were selected for review.Expert Commentary: Karyomapping is currently available for detection of single gene disorders; ~1000 clinics worldwide offer it (via ~20 diagnostic laboratories) and ~2500 cases have been performed. Due an inability to detect post-zygotic trisomy reliably however and confounding problems of embryo mosaicism, karyomapping has yet to be applied clinically for detection of chromosome disorders.

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“…Even with newer approaches to detecting sex chromosome sequences (e.g. [29][30][31][32]) similar problems of misdiagnosis remained.…”

Section: Technical Issues Associated With Pgd/pgsmentioning

confidence: 99%

Karyomapping and how is it improving preimplantation genetics?

Gould

Griffin

2017

Expert Review of Molecular Diagnostics

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“…As described in the current report, MicroSort has been successfully employed in association with intrauterine insemination (IUI) and in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) to achieve numerous pregnancies, currently totaling over 1,300 live-born babies. Levinson et al [ 10 ] reported the first human pregnancy resulting from MicroSort. Fugger et al [ 11 ] reported the births of babies resulting from the use of sorted human sperm for IUI, IVF, or ICSI.…”

Section: Introductionmentioning

confidence: 99%

The effectiveness of flow cytometric sorting of human sperm (MicroSort®) for influencing a child’s sex

Karabinus

Marazzo

Stern

et al. 2014

Reprod Biol Endocrinol

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BackgroundFlow cytometric sorting can be used to separate sperm based on sex chromosome content. Differential fluorescence emitted by stained X- vs. Y-chromosome-bearing sperm enables sorting and collection of samples enriched in either X- or Y-bearing sperm for use to influence the likelihood that the offspring will be a particular sex. Herein we report the effectiveness of flow cytometric sorting of human sperm and its use in human ART procedures.MethodsThis prospective, observational cohort study of the series of subjects treated with flow cytometrically sorted human sperm was conducted at investigational sites at two private reproductive centers. After meeting inclusion criteria, married couples (n = 4993) enrolled to reduce the likelihood of sex-linked or sex-limited disease in future children (n = 383) or to balance the sex ratio of their children (n = 4610). Fresh or frozen-thawed semen was processed and recovered sperm were stained with Hoechst 33342 and sorted by flow cytometry (n = 7718) to increase the percentage of X-bearing sperm (n = 5635) or Y-bearing sperm (n = 2083) in the sorted specimen. Sorted sperm were used for IUI (n = 4448) and IVF/ICSI (n = 2957). Measures of effectiveness were the percentage of X- and Y-bearing sperm in sorted samples, determined by fluorescence in situ hybridization, sex of babies born, IVF/ICSI fertilization- and cleavage rates, and IUI, IVF/ICSI, FET pregnancy rates and miscarriage rates.ResultsSorted specimens averaged 87.7 ± 5.0% X-bearing sperm after sorting for X and 74.3 ± 7.0% Y-bearing sperm after sorting for Y. Seventy-three percent of sorts were for girls. For babies born, 93.5% were females and 85.3% were males after sorting for X- and Y-bearing sperm, respectively. IUI, IVF/ICSI, and FET clinical pregnancy rates were 14.7%, 30.8%, and 32.1%, respectively; clinical miscarriage rates were 15.5%, 10.2%, and 12.7%.ConclusionsFlow cytometric sorting of human sperm shifted the X:Y sperm ratio. IUI, IVF/ICSI and FET outcomes were consistent with unimpaired sperm function. Results provide evidence supporting the effectiveness of flow cytometric sorting of human sperm for use as a preconception method of influencing a baby’s sex.Trial registrationNCT00865735 (ClinicalTrials.gov)

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“…Technology today has progressed to the stage where gender selection has already become a reality for people. The world's first clinical pregnancy from sorted sperm was reported (Levinson et al 1995) some two decades ago, and 22 out of 25 embryos were analysed to be female. The concept of sorting sperm based on DNA is as follows: Sperm is stained with Hoechst 33342, and during the flow cytometry process, X-sperm (which has more DNA contents than the Y-sperm) shines more brightly when passed through the laser.…”

Section: Sorting By Sperm's Chromosomesmentioning

confidence: 99%

Theoretical study of spermatozoa sorting by dielectrophoresis or magnetophoresis with supervised learning

Koh¹

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Assisted reproduction currently accounts for over one in every hundred births in developed countries. The chances of successful conception are closely related to the morphology of sperm used. Despite well-established microfluidic sorting techniques, and reliable mathematical models to quantify the swimming of microorganisms, research on sperm sorting via dielectrophoresis or magnetophoresis lacks theoretical and statistical support. In this thesis, the kinematics of sperm subjected to an external electric or magnetic field is investigated to provide a theoretical framework for computing the resultant velocity. The flagellum waveform is prescribed analytically, and subsequently solved from force and moment balance. The hydrodynamic force acting on the sperm is computed using Resistive Force Theory as well as Slender Body Theory, and the resulting velocity is compared qualitatively and quantitatively. As normal and abnormal sperm cells have different morphological parameters, their velocities under the influence of dielectrophoresis or magnetophoresis are altered to varying extents. This effect is more prominent in a viscoelastic Oldroyd-B fluid than in a Newtonian fluid medium. To account for the natural variations in sperm morphology and beating characteristics, pseudo-random data are generated from a normal distribution. The crosssection of the microchannel is assumed to be much larger than the sperm, such that boundary effects can be ignored. A large number of velocity computations is performed to obtain statistically meaningful results. The difference in velocity distribution between normal and abnormal sperm cells can be widened using an external field to double the proportion of normal ones, with at least half the number of normal spermatozoa in the original sample retained. This sorting has potential to improve the probability of success for intrauterine insemination, given that pregnancy rates are similar as long as the percentage of normal cells exceed a minimum threshold, even if the initial motile sperm count is under a million. Supervised learning is proposed to reduce the computational costs by making predictions after a subset of the data is computed and used for training. By fitting the model to a tenth of the sample size required for statistical convergence, predicted results are precise and accurate to a handful of percentage points. This framework can be adopted to shortlist feasible designs of microfluidic devices before fabrication, as well as assess a wider variety of scenarios in preliminary hypotheses.

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Genetics and human conception: DNA-based X-enriched sperm separation as an adjunct to preimplantation genetic testing for the prevention of X-linked disease

Cited by 59 publications

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Karyomapping and how is it improving preimplantation genetics?

Karyomapping and how is it improving preimplantation genetics?

The effectiveness of flow cytometric sorting of human sperm (MicroSort®) for influencing a child’s sex

Theoretical study of spermatozoa sorting by dielectrophoresis or magnetophoresis with supervised learning

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