Company: BLLN
Filing Date: 2025-10-07
Form Type: S-1
Source: 0001193125-25-233697
Chunk: 211

Company: BillionToOne, Inc.
Filing Date: 2025-10-07
Form: S-1
Chunk 211
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ician and patient includes:

| • |     | Maternal carrier status and any information about the specific variant that may be identified; |

| • |     | A personalized fetal risk score on each condition for which the pregnant mother is a carrier, ranging from <1 in 5,000 
 to 9 in 10, providing clear, actionable information for clinicians and patients; and                                   |

| • |     | Whether the risk is classified as low or high risk. |

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SUMMARY OF RESULTS A POSITIVE Carrier B LOW RISK Fetus 9.0% fetal fraction UNITY Fetal Risk Screen: Carrier Screen + cfDNA Fetal Risk Assessment C CARRIER SCREEN D cfDNA FETAL RISK ASSESSMENT (pregnant carriers only) Conditions Screened Patient Carrier Status Risk Before cfDNA Fetal Risk After cfDNA ACOG Guideline Panel Alpha-Thalassemia Negative N/A HBA1 HBA2 Cystic Fibrosis POSITIVE 1 in 96 -1 in 376 <1 in 5000 E LOW RISK Sickle Cell Disease / Beta- Thalassemia / Negative N/A Hemoglobinopathies HBB Spinal Muscular Atrophy SMN1 Negative 2 SMN1 copies, SNP not presentN/A Maternal Carrier Results Fetal Risk via cfDNA >99% of patients will be reassured with a low risk result1 Conditions screened align with ACOG recommendations2 Fetal risk is provided for this pregnancy without male partner For positive carriers, risk can be clarified down to 1 in 10,000 or up to 9 in 10 1. Internal Data on File, 2024 2. American College of Obstetricians and Gynecologists. (2017) Carrier screening in the age of genomic medicine (Committee Opinion No. 690). Obstetrics & Gynecology, 129(3), e35-e40 UNITY Fetal Risk Screen’s accuracy has been validated in multiple peer-reviewed studies. A 2023 study published in Prenatal Diagnosisdemonstrated 100% of “9 in 10” risk pregnancies were confirmed to be affected pregnancies. 55Because UNITY Fetal Risk Screen does not rely on paternal testing, which is often not completed, it detects up to three times as many affected pregnancies for these recessive conditions compared to traditional carrier screening. 55 Fetal risk stratification from UNITY Fetal Risk Screen UNITY Fetal Risk Screen detects up to three times as