Summary of This Article
In addition to standard NIPT (screening for chromosomal numerical abnormalities such as Trisomies 13, 18, and 21), NIPTy-MONO is a prenatal screening test that evaluates the risk for over 200 single-gene disorders across 155 genes using only a maternal blood sample. Single-gene disorders can occur even without a family history and fall outside the scope of traditional NIPT. The test provides non-definitive screening results, meaning confirmatory testing such as amniocentesis is required for a definitive diagnosis. This test is scheduled to become available sequentially starting in September 2026. Under medical supervision, this article explains the mechanisms of single-gene disorders, key differences from standard NIPT, WES (Whole Exome Sequencing), and WGS (Whole Genome Sequencing), as well as details regarding costs, testing workflows, limitations, and key considerations.
Key Takeaways from This Article
- What single-gene disorders are and how they differ from standard NIPT
- What NIPTy-MONO can detect (155 genes and over 200 target conditions)
- Why single-gene disorder risks can arise even without a family history
- Differences and selection criteria between WES (Whole Exome Sequencing) and WGS (Whole Genome Sequencing)
- Testing workflow, eligible candidates, and costs
- Test limitations, important considerations, and frequently asked questions
We are increasingly hearing from parents who are concerned not only about chromosomal counts, but also about “individual gene variations” when it comes to their baby’s health. In recent years, prenatal screening using maternal blood has expanded from the chromosomal level to the gene level.
Hiro Clinic has accumulated a track record of over 75,000 NIPT procedures (with a 98.8% user satisfaction rate, according to a December 2023 survey by EasyCloud Co., Ltd.). Under medical supervision, this article explains what single-gene disorders are, what NIPTy-MONO can and cannot detect, as well as the testing workflow and costs, while breaking down complex medical terminology. When explaining single-gene disorders in clinical settings, I always make a point to begin by sharing that “these conditions can occur even without a family history.” This is not to cause undue anxiety, but because I believe it is an essential first step toward informed understanding.
What is a Single-Gene Disorder? The Difference Between NIPTy-MONO and Standard NIPT
Understanding “Single-Gene Disorders”
A single-gene disorder is a general term for a disease caused by a variation (mutation) in a single gene. There are over 200 types, including conditions that affect bone and cartilage development, heart structure, and neurological development. Most of the single-gene disorders screened by NIPTy-MONO follow an “autosomal dominant” inheritance pattern, where a condition can develop from a variation in just one gene passed down from either parent. A condition that can affect anyone, regardless of family history—that is the defining characteristic of a single-gene disorder.
“It is commonly believed that if no one in the family has the same condition, there is nothing to worry about. However, as illustrated by the de novo mutation in the diagram above, it is important to understand that having no family history does not mean the risk is zero.
Differences from Standard NIPT
Standard NIPT is a non-invasive screening test that uses fetal cell-free DNA (cfDNA) in maternal blood to detect numerical chromosomal abnormalities, such as Trisomies 13, 18, and 21. In contrast, NIPTy-MONO uses the same maternal blood sample to evaluate variations in individual genes rather than chromosomal counts. Both tests share the common feature of being non-invasive screening tools completed through a standard blood draw.”
| Comparison Item | Standard NIPT | NIPTy-MONO |
|---|---|---|
| Target of Analysis | Numerical chromosomal alterations (Trisomies 13, 18, 21, etc.) | Individual gene variations (Single-gene disorders) |
| Sample Type | Maternal blood (cfDNA) | Maternal blood (cfDNA) |
| Number of Target Conditions | Major chromosomal abnormalities | 155 genes / Over 200 conditions |
| Nature of Test | Non-definitive test (Screening) | Non-definitive test (Screening) |
| Family History Requirement | Does not affect results | Applicable even without family history (Includes de novo mutations) |
In other words, standard NIPT and NIPTy-MONO are not a matter of “which one is superior,” but rather complementary tests that examine different biological levels. Think of them as having distinct roles: standard NIPT checks for chromosomal count, while NIPTy-MONO looks at variations within individual genes. For more details on the positioning of NIPT, the Japan Society of Obstetrics and Gynecology also provides official information.
What NIPTy-MONO Can Detect (155 Genes / Over 200 Conditions)
NIPTy-MONO evaluates the risk of developing over 200 single-gene disorders across 155 genes. The target conditions cover a wide medical spectrum, including skeletal/cartilage, neurological, and cardiovascular systems.
Examples of Target Conditions (Skeletal/Cartilage, Neurological, Cardiovascular Systems, etc.)
Below are some of the relatively well-known conditions included in the comprehensive list. Detailed explanations are also available on the linked pages for each condition.
- Achondroplasia (Causal gene: FGFR3): A condition affecting bone and cartilage growth
- Marfan Syndrome (Causal gene: FBN1): A condition affecting connective tissue and the cardiovascular system
- Neurofibromatosis Type 1 (Causal gene: NF1): A condition affecting the nervous system
- Noonan Syndrome (Causal gene: PTPN11, etc.): A condition affecting the heart and development
- Tuberous Sclerosis Complex (Causal gene: TSC1 / TSC2): A condition affecting the nervous system
These are just a few examples; NIPTy-MONO evaluates many other single-gene disorders as well. If you would like to view the complete list of target conditions, please refer to the list below.
View Full List of Target Conditions (155 Genes / Over 200 Conditions)
The condition names in the list are primarily presented using their official English medical terms, though conditions with commonly recognized Japanese names include those designations. If you do not find a condition that may be relevant to you or your family, or if you would like more detailed information, please consult with us during genetic counseling.
How the Test Works (Analysis of Maternal Cell-Free DNA)
1. Cell-Free DNA (cfDNA) Derived from Maternal Blood
Standard NIPT operates by analyzing fetal-derived cell-free DNA (cfDNA) present in the mother’s blood to estimate risks associated with multiple chromosomes. NIPTy-MONO uses this same maternal cfDNA to evaluate gene variations associated with single-gene disorders.
2. Screening Targets for Single-Gene Disorders (Autosomal Dominant Conditions)
NIPTy-MONO evaluates gene variations related to autosomal dominant conditions. This is a probabilistic screening test and does not provide a definitive diagnosis. A positive result does not confirm the onset of a condition, and a negative result does not rule out all potential risks.
Differences from WES (Whole Exome Sequencing) and WGS (Whole Genome Sequencing)
A major distinction of NIPTy-MONO is that it is a non-invasive screening test completed using only a maternal blood sample, whereas WES and WGS primarily utilize amniotic fluid. Hiro Clinic offers these three testing options for evaluating single-gene disorders.
| Comparison Item | NIPTy-MONO | WES (Whole Exome Sequencing) | WGS (Whole Genome Sequencing) |
|---|---|---|---|
| Sample Type | Maternal blood | Primarily amniotic fluid | Primarily amniotic fluid |
| Target of Analysis | 155 genes / Over 200 single-gene disorders | Known disease genes in exonic regions (~1–2% of the genome) | Entire genome (100%) |
| Positioning | Non-definitive screening test | Detailed diagnostic test to investigate specific causes | Comprehensive diagnostic test including unknown regions |
| Testing Timing | From early pregnancy | Primarily from the period when amniocentesis is performed | Primarily from the period when amniocentesis is performed |
While NIPTy-MONO allows for broad screening through a simple blood draw, it does not provide definitive diagnostic information. If fetal abnormalities or concerning features are detected during an ultrasound, or if you wish to investigate potential genetic causes in greater detail, Whole Exome Sequencing (WES) or Whole Genome Sequencing (WGS) may be appropriate options. You can discuss with your physician to determine which approach best suits your situation.
Eligible Patients & Testing Process
NIPTy-MONO is designed for individuals who wish to understand a broader scope of potential risks, including single-gene disorders, in addition to standard NIPT. The testing process proceeds through the following steps:
- Pre-Test Consultation
- Understanding the test details
- Sharing your reasons for testing and any concerns
- Verifying the qualifications of the medical institution and healthcare providers
- Mandatory genetic counseling
- Sample Collection
- Pregnant patient: Blood draw
- Sample dispatched to the testing laboratory
- Sample dispatched to the testing laboratory
- Analysis
- Results Explanation (Approximately 3 weeks after arrival at the lab)
・Comprehensive feedback provided by specialists
・Discussion of follow-up testing or further consultations as needed
・Confirmation of psychological support and care resources
Note: NIPTy-MONO is scheduled to be available starting September 2026.
Limitations and Important Considerations of the Test
NIPTy-MONO is a non-invasive screening test and does not provide a definitive diagnosis. To help you properly interpret the results, we have summarized the key points you should know in advance. What is essential before undergoing testing is accurate information and clear, honest explanation.
- Not a Definitive Diagnosis: A positive result does not confirm the presence or onset of a condition. Definitive confirmation requires diagnostic testing, such as amniocentesis.
- Does Not Cover All Single-Gene Disorders: NIPTy-MONO evaluates a specific set of 155 genes and over 200 conditions. Other single-gene disorders and non-genetic conditions fall outside the scope of this test.
- A Negative Result Does Not Guarantee Complete Absence of Risk: Conditions caused by variations outside the target regions or by factors not yet understood by current medical science cannot be detected by this test alone.
- Test Availability: NIPTy-MONO is scheduled to become available sequentially starting September 2026. Detailed data regarding test performance and accuracy will be shared upon product launch.。
Interpreting the results requires specialized medical expertise. To prevent misunderstanding and anxiety, please ensure you receive a thorough explanation from a clinical geneticist or certified genetic counselor. For details on cases where results cannot be obtained, please refer to our article on the reasons behind inconclusive test results.
The Purpose of Genetic Counseling
The results of NIPTy-MONO cannot be fully understood simply by looking at numbers or classification names on a test report. The true essence of genetic counseling lies in working alongside specialized physicians and counselors to carefully interpret what these results mean for you and your family.
So You Don’t Have to Process Results Alone
In my clinical practice, I frequently meet patients who attempt to draw conclusions based on fragmented information immediately after receiving their test results. Interpreting these results without specialized knowledge can easily lead to unnecessary anxiety.
Genetic counseling provides dedicated time to consider not only the medical implications of the findings, but also how best to navigate that information moving forward. With a collaborative care network of specialists in obstetrics and gynecology, pediatrics, and clinical genetics, we prioritize creating an environment where you can freely express your questions and concerns at every step. For additional resources on genomic medicine research and support frameworks, information from the Japan Agency for Medical Research and Development (AMED) also serves as a helpful reference.
Cost
The fee for NIPTy-MONO is ¥330,000 including tax (¥300,000 excluding tax). If you are unsure about which plan to choose, we recommend starting with our Plan Assessment Tool to get an initial overview.
| Excl. Tax | Incl. Tax | |
|---|---|---|
| NIPTy-mono | ¥300,000 | ¥330,000 |
Interpreting the test results requires specialized medical knowledge. To avoid misunderstandings or unnecessary anxiety, please ensure you receive a thorough explanation from a clinical geneticist or certified genetic counselor. If you are also considering WES or WGS, we can guide you through the options while comparing the cost differences.
Frequently Asked Questions (FAQ)
Q. When will NIPTy-MONO be available?
A. NIPTy-MONO is scheduled to become available sequentially starting September 2026. For the latest updates regarding the launch date or for initial inquiries, please feel free to schedule a consultation with us at any time.
Q. How does it differ from standard NIPT?
A. Standard NIPT tests for numerical chromosome abnormalities, such as trisomies 13, 18, and 21. While NIPTy-MONO uses the same blood sample, it instead screens for genetic variants associated with over 200 single-gene disorders across 155 genes.
Q. Is there any benefit to taking this test if no one in my family has a genetic condition?
A. Yes. Variations that cause single-gene disorders can include de novo mutations—new mutations that occur spontaneously in the baby without being inherited from either parent. Therefore, a lack of family history does not mean there is zero risk.
Q. When will I receive the results?
A. Results are expected to be available approximately 3 weeks after the sample arrives at the laboratory. As the exact timeframe may vary depending on sample conditions, specific details will be provided during your consultation.
Q. Can I be completely reassured if no variants are detected by NIPTy-MONO?
A. Even if no variants are found among the 155 genes and 200+ conditions covered by NIPTy-MONO, it does not rule out all potential medical conditions. Disorders outside the test scope or those caused by factors not yet understood by medical science fall beyond what this test can identify.
Q. What is the difference between NIPTy-MONO, WES, and WGS? Which one should I choose
A. NIPTy-MONO is a non-invasive screening test requiring only a blood draw. If ultrasound findings reveal concerning features or if you wish to investigate potential causes in greater detail, Whole Exome Sequencing (WES) or Whole Genome Sequencing (WGS)—which primarily utilize amniotic fluid—serve as diagnostic options. You can discuss with your physician to decide which test is most appropriate for your situation.
Author & Medical Supervisor
Hiroshi Oka, M.D., Ph.D. / General Director & Lab Director of Hiro Clinic (Fukumikai Medical Corporation). After graduating from Keio University School of Medicine, Dr. Oka passed both the Japanese and U.S. medical licensing examinations and earned his Ph.D. in Medicine. He is one of only about 20 certified Clinical Laboratory Directors in Japan. He also serves as a visiting professor at a professional university and shares evidence-based information on pregnancy and prenatal diagnosis through platforms such as his YouTube channel, “Dr. Hiroshi’s Evidence-Based Pregnancy Channel.” References: The Japan Society of Human Genetics, Japanese Association of Medical Sciences “Guidelines for Genetic Testing and Diagnosis in Medicine”, Japan Intractable Diseases Information Center, and our clinic’s Editorial and Medical Supervision Policy.
