Understanding 47,XYY Syndrome

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Article by Dr. Ha Thi Lien - Medical Genetics Division, Vinmec High-Tech Center

47,XYY syndrome, also known as Jacob's syndrome, is a syndrome in which a man has an extra Y chromosome (46,XY). The majority of men with this syndrome are taller than average and do not have other phenotypic abnormalities. These people still develop normal male sex, have the male sex hormone testosterone and still have the ability to have children.

1. Clinical features

47,XYY syndrome is often accompanied by an increased risk of language delays, speech delays, and learning difficulties. Children with this syndrome may also have developmental delays in motor functions such as sitting, walking, or myasthenia gravis. Some of the other signs include tremors, involuntary movements, seizures or asthma. Boys 47,XYY may have psychological, social, and personality development difficulties compared to their peers, such as: attention deficit hyperactivity disorder (ADHD), depression or autism spectrum syndrome. ..

Bị sụp mí do bệnh nhược cơ có thể phẫu thuật kéo mí không? — Trẻ có thể bị nhược cơ khi mắc hội chứng 47,XYY

2. Incidence

The prevalence of 47.XYY syndrome is 1/1000 male infants. Every day in the US, 5 to 10 boys are born with this syndrome. Many boys with this syndrome go undiagnosed or only diagnosed in adulthood.

3. Genetic causes

Normal people have 46 chromosomes in which there are 2 sex chromosomes, X and Y. Females have XX sex chromosomes, males have XY pairs of sex chromosomes. People with 47,XYY syndrome are caused by the presence of an extra Y chromosome in males. As a result, the male has a total of 47 chromosomes and an XYY sex chromosome instead of 46.
Some people have a mosaic of 47,XYY syndrome where only some cells in their body have an extra Y chromosome and others are normal.

Nguyên nhân gây ra hội chứng 47,XYY là do quá trình tạo tinh trùng

Most 47,XYY syndromes are caused by a new mutation, not by genetics. This mutation can occur during spermatogenesis, when 2 Y chromosomes do not separate during cell division resulting in 1 sperm having 2 Y chromosomes and one sperm having no chromosomes. Y. The union of a normal egg with a sperm with 2 Y chromosomes produces a zygote with a sex chromosome of XYY.
Males with cell line mosaic 46,XY/47,XYY also occur due to errors in early embryonic development. Chromosomes do not segregate evenly resulting in some cells having 46 chromosomes (46,XY) and some cells having 47 chromosomes (47,XYY).

4. Diagnosis

47,XYY syndrome can be easily detected by chromosomal testing (Karyotype).

xét nghiệm nhiễm sắc thể — Xét nghiệm nhiễm sắc thể cho phép chẩn đoán hội chứng Jacob

Vinmec International General Hospital has performed chromosomal testing to diagnose 47,XYY syndrome.

Please dial HOTLINE for more information or register for an appointment HERE. Download MyVinmec app to make appointments faster and to manage your bookings easily.

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This article is written for readers from Sài Gòn, Hà Nội, Hồ Chí Minh, Phú Quốc, Nha Trang, Hạ Long, Hải Phòng, Đà Nẵng.