Compilation of NIPT test results for more than
10,000 pregnant women in Japan

NIPT testing for pregnant women in Japan
using Illumina equipment (10,007 cases)

HUMEDIT NIPT has performed more than 10,000 tests (June 2020 – June 2021). In collaboration with Tokyo Clinical Laboratory, we have examined 10,007 pregnant women who took the Full set plan available in HUMEDIT NIPT, and we determined what are the most appropriate tests for pregnant women in Japan and which tests are appropriate for which age groups.

This data analysis was performed under the following conditions:

What results can be expected without the ’35+ age limit’ recommended by the NIPT Consortium? This has not been verified to date.
Data on all other autosomes (including sex chromosomes) and whole region partial deletions and duplications have not been reported in Japan, although the positivity rates of chromosomes 21, 18, and 13 have been reported.

In NIPT studies around the world, it is known that genetic disorders have ethnic and regional characteristics.
However, despite the availability of various research data, mainly from Europe and the U.S. but also from Asia, there have been no reports of genetic disease data exclusively on pregnant women in Japan.

HUMEDIT NIPT hopes that the ‘NIPT test results of more than 10,000 pregnant women in Japan’ derived from our past tests will be made public and will help pregnant women to choose the right test. HUMEDIT NIPT places the utmost importance on protecting the right to know of all concerned parties, including pregnant women. (As of June 21, 2021)

Total # of people	10,007
Over 35 years old	5,002	50.0%
Under 35 years old	5,005	50.0%

Oldest positive individual	47 years old
Youngest positive individual	24 years old

Number of positive patients	245	2.45%
Positive cases over 35 years old	175	3.50%
Positive cases under 35 years old	70	1.40%

According to the latest examination statistics, only 50% of pregnant women are over the age of 35.
This is a clear indication that more and more pregnant women under the age of 35 come to be examined.
At HUMEDIT NIPT, the overall positivity rate is 2.45%; the positivity rate for those over 35 years old is 3.50%, which is 2.5 times higher than the 1.40% positivity rate for those under 35 years old. This is because there are actually about 3 times more births under the age of 35, so the estimated number of abnormalities under the age of 35 is about 1.2 times (= 1.40 / 3.50 X 3) higher than the number of abnormalities over the age of 35.

Age of Pregnant Women	Trisomy 21	Trisomy 18	Trisomy 13	Sex chromosome	Other autosomes	All autosomal whole region partial deletions/duplications	Total
Total Positive in every case	67	44	16	31	52	44	254
Number of all positive individuals	67	44	16	31	52	35	245
Over 35 years old	54	38	9	17	36	28	182
Under 35 years old	13	6	7	14	16	16	72

※ Cases with multiple diseases are counted individually.

Of those who tested positive, 27.35% had Chromosome 21 trisomy, 17.96% had Chromosome 18 trisomy, and 6.53% had Chromosome 13 trisomy, accounting for half of the total. On the other hand, aneuploidy (abnormal number of chromosomes) of chromosomes other than 13, 18, and 21 accounted for 35% of the total, including 21% of autosomes and 13% of sex chromosomes.

Whole region partial deletions and duplications may have various clinical findings depending on their size and location. However, since the number of whole region partial deletions and duplications detected by HUMEDIT NIPT is more than 7 million bases, even if 2% of them are considered to be in the exonic region, monosomy and trisomy of approximately 140,000 bases are likely to cause some disorders in patients with the disease.

Testing coverage of 10,007 NIPT tests (June 2021)

Test coverage is the percentage of cases that are positive for the selected test plan.

	Chro.21	Chro.18	Chro.13	Sex chromosome	Other autosomes	All Autosomal Regions Partial deletion/duplication
Positive Location	67	44	16	31	52	44
Number of Positive Individuals	67	44	16	31	52	35

The bar graph above shows the numerical ‘Test Coverage Percentage’ of the test plans that are frequently chosen by pregnant women at HUMEDIT NIPT.
The test coverage rate is of the minimum plan is 51%, while the Over35 plan, which is recommended for pregnant women over 35 years old, has a test coverage rate of 85%. The 51% test coverage means that 49% of the diseases are returned negative.
The second plan from the left is the ‘Recommended Plan’ of HUMEDIT NIPT, which is a cost-effective plan with only selected test items that have been tested positive by 10,007 people. For those who would like to ensure complete coverage of results, we recommend the Full Set Plan.