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03.11.25

5 Hidden Genetic Disorders Parents Unknowingly Transfer to a Child.

5 Hidden Genetic Disorders Parents Unknowingly Transfer to a Child.

Every family dreams of passing on good health to their children. But even if parents appear completely healthy, they may unknowingly pass recessive genes that can cause genetic disorders in their children. Understanding this hidden risk is an important step for planning to have a baby.

What Are Genetic Disorders and How Do They Happen?

Genetic disorders occur when there’s a change or mutation in genes or chromosomes that affects the body’s normal functions. These changes can be inherited from one or both parents.

Being a carrier means having one copy of a mutated gene without showing symptoms of the disease. However, if both parents carry the same recessive gene, there’s a 25% chance that their child could inherit both abnormal genes and be affected by the condition from birth.

There are several types of genetic inheritance, but the one related to carrier status is called autosomal recessive inheritance. This pattern occurs when a child inherits a faulty gene from both parents, leading to the expression of the disease.

  • 25% chance the child will have the disease
  • 50% chance the child will be a carrier
  • 25% chance the child will have normal genes

Another form of inheritance is X-linked recessive inheritance, which typically involves the X chromosome. Women (XX) can carry the gene without symptoms, but when passed on to male offspring (XY), the child has up to a 50% chance of being affected.

Because carrier parents often show no signs of illness, these hidden risks can only be detected through Expanded Carrier Screening (ECS)—a proactive genetic test that helps uncover silent mutations before they are passed on to the next generation.

5 Common Genetic Disorders Parents May Carry

1. Thalassemia

A type of inherited anemia caused by abnormal red blood cell production. Children with Thalassemia often suffer from chronic fatigue, enlarged spleen or liver, and require lifelong blood transfusions and iron chelation therapy.

Carrier frequency in General Population: 1 in 25 people*

2. Spinal Muscular Atrophy (SMA)

A severe genetic disorder that causes progressive muscle weakness, leading to difficulty in movement, swallowing, or breathing. It is one of the leading genetic causes of infant mortality.

Carrier frequency in General Population: 1 in 54 people*

3. Fragile X Syndrome

A genetic condition linked to the X chromosome and one of the most common causes of inherited intellectual disability. A mother who carries the gene has a 50% chance of passing it to her son, who is more likely to show symptoms.

Carrier frequency in General Population: 1 in 500 people*

4. G6PD Deficiency

Caused by low levels of the G6PD enzyme, which protects red blood cells from oxidative damage. Exposure to certain foods, drugs, or chemicals can cause red blood cell breakdown, leading to jaundice or severe anemia.

Carrier frequency in General Population: 1 in 30 people*

5. GJB2 Gene Mutation (Congenital Hearing Loss)

In some cases, this gene mutation is a major genetic cause of permanent hearing loss from birth, affecting a child’s ability to develop normal speech and communication.

Carrier frequency in General Population: 1 in 4102 people*

*varies by ethnicity

Why You Should Consider Expanded Carrier Screening

Expanded Carrier Screening (ECS) is a powerful genetic test that helps identify whether you and your partner carry the same recessive genes that could lead to a genetic disorder in your future child.

Benefits of Expanded Carrier Screening:

  • Understand your risk early

Knowing your carrier status helps couples make informed decisions before pregnancy.

  • Plan for healthy conception

If both partners are carriers of the same genetic condition, doctors may recommend IVF or ICSI combined with embryo genetic testing (PGT-M) to select embryos free of specific diseases.

  • Confidence for the future

Having clear genetic information reduces anxiety during pregnancy, supports long-term health planning, and helps avoid potential treatment costs for genetic diseases.

  • Prepare ahead! even if you’re not ready yet

Knowing your genetic profile helps you make proactive choices about your reproductive future.

Understanding your genetic background doesn’t just protect your future child—it empowers you to plan confidently for your family’s future.

At SAFE Fertility Clinic, we offer Expanded Carrier Screening to evaluate your risk of inheritable diseases. Our fertility specialists and certified genetic laboratory teams use advanced technology under international standards to help transform concern into clarity—so every couple can move forward toward a healthy family with confidence.

Article by: Kamolrat Mee-o-partmongkon, M.D. (Dr.Bo)
SAFE Fertility Group PCL, Gaysorn Amarin and Ramintra Branch
Medical License Number 41300

Reference

  • Carrier Screening for Genetic Conditions. American College of Obstetricians and Gynecologists. https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/03/carrier-screening-for-genetic-conditions
  • Expanded carrier screening for reproductive risk assessment: An evidence-based practice guideline from the National Society of Genetic Counselors. J Genet Couns. https://pubmed.ncbi.nlm.nih.gov/36756860/
  • โรคธาลัสซีเมีย. คณะแพทยศาสตร์ศิริราชพยาบาล.
    https://www.si.mahidol.ac.th/th/healthdetail.asp?aid=325
  • โรคกล้ามเนื้ออ่อนแรง Spinal Muscular Atrophy: SMA. ศูนย์กล้ามเนื้ออ่อนแรงศิริราช.
    https://www.si.mahidol.ac.th/th/division/SiNMD/knowledge_detail.asp?id=4
  • โรคพร่องเอนไซม์ G6PD. สมาคมโลหิตวิทยาแห่งประเทศไทย.
    https://www.tsh.or.th/Knowledge/Details/43
  • การตรวจคัดกรองพาหะทางพันธุกรรม: ก้าวสำคัญสู่ครอบครัวที่สมบูรณ์. ศ.เกียรติคุณ ดร.วสันต์ จันทราทิตย์. คณะแพทยศาสตร์โรงพยาบาลรามาธิบดี.
    https://www.rama.mahidol.ac.th/rama-km/cat/main/undefined/4298
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