Patient's question:
I am from Shandong, I am 28 years old this year, and I have been married for 5 years. So far, I have no children. The doctor checked and said that my husband has a low sperm count and weak sperm motility. I went to the hospital for in vitro fertilization, which is artificial insemination. I was pregnant for 2 months, but the fetus died unexpectedly. The examination said that it was due to abnormal chromosomes in my husband. What should I do?Doctor's answer:
Hello, chromosomal abnormalities cannot be cured. The key is to determine whether they are hereditary (on autosomes or sex chromosomes, etc.), and what the probability is that the baby will inherit the mutated gene. Overall statistics are around 30%. If it is X-linked dominant inheritance, and your husband is healthy, then there is a 50% chance that the children will be healthy.2. It depends on the specific chromosomal abnormality, but the probability of being able to have children is very high. "Balanced translocation" occurs in the general population at a rate of 1.9%. Patients with chromosomal balanced translocations have a high risk of miscarriage and giving birth to malformed children, while the proportion of healthy children is less than one-third.
The name of the 18p deletion syndrome is also known as Grouchy-Royer-Salmo-Lamy syndrome or 18q syndrome. It is a severe mental retardation and malformations of the reproductive system caused by the absence of the long arm of chromosome 18. The etiology is unclear. Clinical manifestations include severe mental retardation, talipes equinovarus, microcephaly, skin nodules at the nasal folds, slender fingertips, wide distance between the nipples, underdeveloped labia minora in females, and small penis with cryptorchidism in males. Congenital heart defects, blood immunoglobulin deficiency, and chromosomal testing can aid in diagnosis, but there is no specific treatment.
Definition: When two non-homologous chromosomes undergo an exchange, the gene composition and phenotype remain unchanged. This type of translocation generally has no serious impact on gene expression or individual development.
Detailed content: Humans have 23 pairs of 46 chromosomes, and the number and structure of chromosomes are relatively constant and cannot be arbitrarily increased or decreased, otherwise problems may arise. Chromosomal balanced translocation refers to the exchange of two chromosomes after breaking, with only positional changes and no visible increase or decrease in chromosomal fragments. This translocation causes "internal relocation" of chromosomal genetic material. However, for a single cell, the total number of chromosomes remains unchanged, and the genes it contains are not increased or decreased, so carriers of balanced translocations usually do not exhibit abnormal phenotypes, and their appearance, intelligence, and development are typically normal. However, when carriers of balanced translocations marry normal individuals and have children, there is a possibility of inheriting a derivative abnormal chromosome, leading to an increase (partial trisomy) or decrease (partial monosomy) of a specific translocation segment and producing corresponding effects. Since a fetus inherits one chromosome from each parent to form its own chromosomes, if it does not inherit all the translocated chromosomes from the father (mother) or all the normal chromosomes from the father (mother), but only inherits one translocated derivative chromosome, this would result in an imbalance in the total amount of genetic material, leading to a deletion (partial monosomy) or excess (partial trisomy) of a specific translocation segment. This disrupts the balance of genetic material, causing fetal malformations or spontaneous abortions.
Chromosomes are arranged in a certain order, containing a specific number of genes. If the integrity of the chromosomes is disrupted due to internal or external reasons, it can cause disease, known as a chromosomal disease. Chromosomal abnormalities are also called chromosomal aberrations, including numerical abnormalities and structural abnormalities.
(1) Numerical abnormalities: The number and structure (shape) of chromosomes in a cell are relatively stable but variable. The increase or decrease in the number of chromosomes generally accounts for only 1–2%, and the maximum does not exceed 5%. As for structural changes in chromosomes, they generally do not exceed 1%. Diseases caused by numerical abnormalities include autosomal abnormalities such as Down syndrome, where the karyotype of the affected child is often 47,XX (XY),+21, indicating an extra 21st chromosome compared to normal, which is also known as trisomy 21. Diseases caused by numerical abnormalities of sex chromosomes include: ① Klinefelter syndrome, with a karyotype of 47,XXY. One-third of patients have a karyotype of 46,XY/47,XXY mosaicism. One normal testicle may be present with fertility. ② Gonadal dysgenesis: Patients have negative X chromatin, with a karyotype of 45,X. There is also a mosaicism karyotype of 45,X/46,XX.
(2) Structural abnormalities: Due to certain reasons, a chromosome may break off from its long axis, called a break. The fragment after the break can undergo abnormalities such as deletion, translocation, inversion, and duplication due to different movements. The most common diseases caused by structural abnormalities include 14/21 translocation-type Down syndrome, with a karyotype of 46,XX (XY),-14,+t(14q21q), meaning the karyotype is missing one 14th chromosome and has an extra translocation chromosome formed by the long arm of chromosome 14 and the long arm of chromosome 21.
Examples:
1. After chromosomal testing, my 9th chromosome is 9qh+. Can I have children? I am the male.
Answer: Chromosomal testing, 9qh+, refers to an increase in part of the long arm of the 9th chromosome. I don’t know what your question is regarding chromosomal testing. Of course, if there are no symptoms, it may correspond to normal chromosomes for compensation. In the future, when forming gametes (whether male or female), there is still a possibility of passing it on to offspring.
2. Hello experts, please help me review my chromosomal report. My G-banded karyotype is 46,XX,1qh+(genetic polymorphism). My husband’s G-banded karyotype is 46,XY, with no obvious abnormalities. Are we normal? Please reply, thank you!
Answer: G-banded karyotype: 46,XX,1qh+(genetic polymorphism) is not normal and may have an adverse effect on future fertility.
Question: What does qh+ in the chromosome mean?
Answer: Hello, q indicates the long arm of the chromosome, h indicates the secondary constriction, and + indicates an increase. The occurrence rates of inv(9) and 9qh+ in humans depend on race, and because carriers often show no abnormalities, they have been considered normal polymorphisms. However, some literature has suggested that inv(9) and 9qh+ are associated with fertility difficulties and various diseases. This study aims to investigate the occurrence rates of inv(9) and 9qh+ in Taiwanese people and analyze their clinical correlation with diseases. We screened 4,752 independent samples (including 3,070 amniotic fluid samples and 1,682 peripheral blood samples from suspected chromosomal disease patients) for inv(9) and 9qh+, and analyzed their correlation with clinical diseases. The results of the amniotic fluid study showed that the occurrence rate of inv(9) in Taiwanese people is 1.2%, while the occurrence rate of 9qh+ is 7.21%, with significantly more females than males. Additionally, the blood study results showed that inv(9) and 9qh+ are associated with several different diseases and are also factors that adversely affect fertility. The occurrence rate of 9qh+ is also high in Down syndrome patients. Based on these results, we recommend that genetic counselors and prenatal health physicians explain to carriers of inv(9) or 9qh+ that these are normal polymorphisms but also inform them of their possible correlation with diseases.
Regarding the treatment of chromosomes, so far, there is no clinical treatment that guarantees the absence of fetal malformations. It depends on the specific abnormal gene carried. It is best to consult a genetic expert.