What is POCScreening?

Having a miscarriage is a traumatic event, often leaving you with questions about what happened.

More than half of first-trimester miscarriages are caused by chromosome abnormalities.1

The POCScreen test offered by Next Biosciences employs next generation sequencing (NGS) technology to rapidly and accurately screen products of conception for abnormal chromosome numbers, and large genetic deletions and/or duplications of chromosomal material.

Chromosomal Abnormalities

Humans have 23 pairs of chromosomes (46 in total) within almost every cell in our body

One chromosome of each pair comes from our mother, and the other from our father. The first chromosome pairs are labelled 1-22. The last pair of these chromosomes are the sex chromosomes, which determine sex. Females usually have two X chromosomes, and males have an X and a Y chromosome. A change in the number of chromosomes is called aneuploidy and can lead to a change in development resulting in a miscarriage. Having an extra copy of a chromosome is called a trisomy (three copies), while missing a copy of a chromosome (having only one copy) is called a monosomy.

The majority of aneuploidies are not compatible with life and result in miscarriage. POCScreen is a comprehensive analysis of all 23 chromosomes: 22 autosomes and the sex chromosomes X and Y. The use of high-resolution NGS also allows for the detection of structural rearrangements and POCScreen can determine whether a miscarriage was caused by a chromosomal abnormality.

Why do a POCScreen?

Although many chromosomal abnormalities that cause miscarriages are sporadic and have a low recurrence risk, some abnormalities (such as translocations) are expected to significantly increase the risk of recurrence- which may necessitate parental karyotyping.

By identifying the (approximately) 50% of women whose pregnancy loss was due to chromosomal abnormalities, comprehensive chromosome screening will prevent a large proportion of patients undertaking unnecessary and costly evaluations. Furthermore, the psychological benefit of identifying the aetiology of a foetal loss, cannot be understated.

If a foetal chromosomal abnormality is excluded, there may be a possible treatable cause for a given miscarriage, and investigations can be focussed on identifying this.

Genetic testing outcomes can therefore be used to guide counselling for future pregnancies.

What are the advantages of Products of Conception Screening using NGS?

CLICK TO SEE ADVANTAGES
  • Coverage of all chromosomes in the genome (1-22, X&Y)
  • High resolution
  • >99% analytical specificity
  • >99% diagnostic accuracy
  • >99% analytical sensitivity
  • No need for cell culturing
  • Test failure rate of 0.1%
  • Pick-up rate of approximately 50%
  • Fast turnaround time (7-10 working days)

References

1 Wapner et al. (2012) NEJM 367 (23): 2175-2184. 2 Jeve et all. J Hum Reprod Sci. 2014 Jul-Sep; 7(3): 159–16

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