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:
- No age limit for testing
- No restriction on
target chromosomes
- Limited to pregnant
women in Japan
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.
Source: HUMEDIT Research
| 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.
Source: HUMEDIT Research
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.
Source: HUMEDIT Research
Source: HUMEDIT Research
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.
