Thu, 32, gave birth to premature twins at 34 weeks due to unexplained water breaking three years ago. Her son showed signs of developmental delays, which the family attributed to birth complications. Recently, the couple sought pre-pregnancy screening at Tam Anh General Hospital, District 7, as they planned for a second child.
Doctor Nguyen Phuong Thao, from the Fetal Medicine Unit, analyzed the genetic results of their son and discovered a homozygous mutation in the ASPM gene, which causes microcephaly and developmental delays. Genetic testing confirmed that both parents carry a recessive mutated ASPM gene without exhibiting symptoms of microcephaly (also known as microcephaly syndrome), meaning they are healthy carriers.
The ASPM gene is inherited recessively on chromosome one and can cause microcephaly, leading to mild to severe language and intellectual development delays. According to Dr. Thao, genetic techniques can help investigate various abnormalities. These include karyotype tests for chromosomal abnormalities, Fragile-X tests for common developmental delay causes, CGH-array tests for structural chromosomal abnormalities, and next generation sequencing (NGS). In Thu's case, each pregnancy carries a 25% risk of microcephaly, a 50% risk of the fetus inheriting one mutated gene copy and one normal copy, and a 25% chance of a healthy child.
Before Thu's second pregnancy, Dr. Thao advised her to undergo chorionic villus sampling (at 11-13 weeks) or amniocentesis (at 16 weeks) to diagnose any genetic abnormalities and determine the optimal course of action. If the couple opted for in vitro fertilization (IVF) to eliminate the risk of having a child with the condition, preimplantation genetic testing for monogenic disorders (PGT-M) could be performed. After careful consideration, the couple decided to conceive naturally and follow regular check-ups and ultrasounds as advised.
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Dr. Thao provides genetic counseling to a couple. Illustrative photo: Tam Anh General Hospital, District 7 |
According to Dr. Thao, ASPM gene mutations account for 10-40% of congenital microcephaly cases. Microcephaly linked to this gene mutation typically presents with a small head, intellectual and speech delays, short stature, and other symptoms. Treatment primarily focuses on managing symptoms. Children require regular monitoring, care, speech therapy, education, behavioral control, mobility support, and management of spasticity or epilepsy (if present). Around 33% of children with genetic disorders are born to healthy parents or those with no family history. Approximately half of these congenital disorders are caused by single-gene variants, detectable through genetic testing. Therefore, couples planning to conceive or currently pregnant should undergo genetic screening, especially high-risk groups, such as those with a history of birth abnormalities, miscarriage, stillbirth, or family history of birth defects.
If a couple is found to have genetic abnormalities, doctors provide genetic counseling and develop appropriate prevention and treatment plans to avoid recurrence in subsequent pregnancies. Pre-pregnancy or prenatal genetic screening contributes to optimal pregnancy management, psychological preparation, and cost planning for treatment if the fetus is diagnosed with a condition, according to Dr. Thao.
Dr. Thao recommends pregnant women adhere to their prenatal check-up schedule, especially during the thu nhat trimester (11-13 weeks and 6 days), for early detection of fetal abnormalities through ultrasound. Pregnant women can also undergo non-invasive prenatal testing (NIPT) to screen for abnormalities. If abnormalities are detected through NIPT or ultrasound, chorionic villus sampling or amniocentesis can be performed to pinpoint the cause.
Ngoc Chau
*The patient's name has been changed.
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