Hotspot Analysis
Recently, a pregnant woman in Sichuan was found to have a fetus with Klinefelter syndrome during a prenatal check-up, sparking heated discussions among netizens about topics related to Klinefelter syndrome.
So, what is the truth? Is the reality as terrifying as the rumors suggest?
01
What is Klinefelter Syndrome?
Klinefelter syndrome, also known as 47, XYY syndrome, is one of the most common sex chromosome aneuploidy abnormalities. The ratio in males is about 1 in 1000. Normal males have 2 sex chromosomes – X and Y, while males with Klinefelter syndrome have an extra Y chromosome.
Research suggests that only 15% of males with Klinefelter syndrome are diagnosed, while the majority are indistinguishable from normal individuals in the vast population.
02
What is the “Devil Gene” all about?
The term “Devil Gene” originated from a publication. In 1965, a study published in the journal “Nature” found that among 197 “psychiatrically abnormal males with dangerous, violent, or criminal tendencies,” 8 individuals had an extra Y chromosome. In contrast, no extra Y chromosomes were found in 200 randomly selected normal males and 200 male infants. Based on this, researchers speculated a relationship between violent behavior and this extra Y chromosome.
Although many subsequent studies do not support this view, the term “Devil Gene” has been widely circulated. In fact, this view was flawed from the beginning as the biased selection of study subjects led to skewed research conclusions.
Of course, it is observed that the occurrence of antisocial behavior is slightly higher in some males with Klinefelter syndrome, not due to elevated male hormones (studies indicate that testosterone levels in males with Klinefelter syndrome are mostly within normal range), but possibly due to changes in their cognitive functions leading to poorer economic conditions and lower social status, indirectly increasing the crime rate.
Therefore, some scholars have proposed screening for sex chromosome abnormalities in newborns to help families understand disease risks early, adopt scientific parenting methods, and intervene promptly in the development, physical and mental health, academics, etc., of affected children.
03
What are the symptoms of “Klinefelter Syndrome”?
It is important to note that all research on sex chromosome abnormalities may have biases, considering that there may be 85% of males with Klinefelter syndrome who have never been diagnosed. Compared to other types of sex chromosome abnormalities, there is less research on XYY, and therefore these results may not fully represent the entire population with Klinefelter syndrome.
Males with Klinefelter syndrome generally have no distinctive differences in appearance from normal males, but are taller, have normal or slightly enlarged testes, normal pubertal development, normal or within normal lower limit levels of testosterone, and may have symptoms such as flat feet, knocked knees, or club feet.
Data from the UK Biobank shows that adult males with Klinefelter syndrome have higher body mass index (BMI), body fat percentage, and blood lipid levels, increasing the risk of type 2 diabetes, obesity, and asthma, indicating a higher likelihood of metabolic abnormalities.
The cognitive functions of males with Klinefelter syndrome may be the most concerning issue for parents and researchers. Some males with Klinefelter syndrome may have behavioral and learning disorders, mild delays in language and motor development, increased risk for autism spectrum disorders and attention deficit hyperactivity disorder (ADHD), which may reduce their abilities to regulate emotions, behaviors, attention, etc., resulting in difficulties in social adaptation and interpersonal behaviors.
The fertility of males with Klinefelter syndrome is generally normal, and they may potentially have offspring with normal sex chromosomes through natural conception with their partners. However, some research has found that some males with Klinefelter syndrome may have fertility disorders or an increased risk of offspring with sex chromosome abnormalities. This group can use assisted reproductive technology to help their partners conceive and have healthy offspring.
Reminder
With the widespread use of non-invasive prenatal testing (NIPT) for free fetal DNA in maternal blood, the prenatal diagnosis rates of 47, XXX (Triple X syndrome), 47, XYY (XYY syndrome), and 47, XXY (Klinefelter syndrome) continue to rise. During genetic counseling, doctors will help each family make the most suitable choices rather than providing a definitive answer. In consultations with families of fetuses diagnosed with Klinefelter syndrome, doctors will objectively inform them of possible clinical outcomes, and then it is up to the family to decide whether to continue the pregnancy based on their own circumstances. Regardless of the choice each family makes, it is understandable. Despite advancements in medicine, there is still much unknown in the medical field, and many questions may not have definitive answers.
Article Author: Jia Nan
Doctor of Obstetrics and Gynecology, Associate Chief Physician.
Specializes in prenatal diagnosis, genetic counseling, perinatal care, common obstetric complications, and the diagnosis and treatment of common gynecological diseases.
Genetic Counseling Clinic (Yangpu Campus): Wednesday Afternoons
Review Expert: Xiong Yu
Chief of Obstetrics, Director of the Fetal Medicine Center, Chief Physician, Doctoral Supervisor.
Specializes in complex twin/multiple pregnancies, intrauterine growth restriction of fetuses, and the diagnosis and treatment of fetal deformities (structural deformities and genetic syndromes). Has extensive experience in high-risk pregnancies (gestational hypertension, diabetes, preterm birth), adverse obstetric history (recurrent miscarriage, stillbirth), perinatal care, etc.
This article was first published in “Health Report” Editor: Liu Yang
