congenital testicular hypoplasia
Introduction
Introduction to congenital testicular hypoplasia Congenital testicular hypoplasia, also known as seminiferous tubule hypoplasia or primary small testicular disease or Klinefeltersyndrome, described by Klinefelter, Reifenstein, and Albright in 1942, characterized by small testes, no sperm and urinary gonads Hormone increase and so on. In 1959, Jacobs et al found that the patient's sex chromosome was 47,XXY, which is one more X chromosome than normal males. Therefore, this disease is called 47,XXY syndrome. The fundamental flaw is that males have one more X chromosome, and the common karyotype is 47, XXY or 46, XY/47, XXY. basic knowledge Sickness ratio: 0.01%-0.02% Susceptible people: male Mode of infection: non-infectious Complications: cleft palate cryptorchidism
Cause
Congenital testicular hypoplasia
(1) Causes of the disease
The formation of congenital testicular hypoplasia may be due to the egg cell in the process of mature division, the sex chromosome does not separate, forming an egg containing two X, if this egg is combined with Y sperm to form 47,XXY fertilized egg, if spermatogenic cells In the process of maturity, the first mature division XY does not separate, then XY sperm is formed. This sperm can also form 47,XXY fertilized eggs in combination with X eggs. It is generally believed that most of the 47,XXY forming eggs are in mature division. In the process, the sex chromosomes are not separated.
(two) pathogenesis
So far, the karyotype of this disease has been found to be more than 30 species. The vast majority of patients have a karyotype of 47,XXY, accounting for 80% of all cases, and about 15% of patients have chimeras with two or more cell lines. Among them, 46, XY/47, XXY (about 7%) and 46, XY/48, XXXY chimeric type, the former has a mild clinical performance of 47, XXY, and 1% of patients have karyotype. It is 46, XX/47, XXY, but the phenotype is no different from that of typical congenital testicular hypoplasia. The karyotype of some patients with typical clinical manifestations is 46, XX. The explanation for this strange phenomenon is: The patient was a chimera 46, XX/47, XXY in embryonic development, but the XXY cell line disappeared later, or the latter was extremely small and thus not detected.
In addition to chimeric in vitro, there are many variant types of congenital testicular hypoplasia, such as 48, XXYY, 48, XXXY, 49, XXXXY, 49, XXXYY, etc. The more X chromosomes a patient has, the more severe the mental retardation, the masculinization disorder The degree is also more obvious, accompanied by physical deformity, some XXXY patients have ulnar and tibia ossification combined, XXXXY patients also have craniofacial and limb deformities, but no matter how many X chromosomes increase, as long as there is Y chromosome determines its performance The type is male.
Prevention
Congenital testicular hypoplasia prevention
Chromosomal malformations of congenital testicular hypoplasia, in the elderly women with more chances in pregnancy, can refer to the relevant preventive measures of genetic diseases:
1. Prohibit close relatives from marrying and avoiding older pregnancies.
2. Premarital examination to discover genetic diseases or other diseases that should not be married.
3. The detection of the carrier: through the group census, family survey and pedigree analysis, laboratory tests and other means to determine whether it is a genetic disease, and determine the genetic mode.
4. Genetic counseling:
(1) Genetic counseling:
1 Patients diagnosed with hereditary diseases and their relatives.
2 consecutive families with unexplained diseases.
3 congenital primary intelligence is low, suspected of genetic related.
4 balance translocation chromosomes or carriers of disease-causing genes.
5 Women with unexplained recurrent miscarriage.
6 sexual dysplasia.
7 have a family history of hereditary diseases and intend to marry and give birth.
(2) The main objectives of genetic counseling:
1 pair of patients themselves:
A. Determine the diagnosis of the disease, the cause of the disease, the genetic pattern, the treatment and the prognosis, and further analyze whether the patient's disease-causing gene or chromosomal abnormality is caused by a new mutation or a previous generation.
B. Relieve the physical and mental pain and anxiety of the patient.
C. Give early attention to patients who are not ill, and give necessary treatment.
2 For both parents and relatives:
A. Detection of carriers and recessive cases in the family.
B. Determine the risk of developing a member of the family.
C. Help couples who are at risk of having children with genetic diseases to help them scientifically and consider birth plans in accordance with family planning regulations.
(3) Genetic estimation of pediatric diseases:
1 The difference between the diseases of children is the intrauterine environmental factors, the birth injury and the pathogenesis of hypoxia-ischemia or genetic factors, so it is necessary to understand the history of the parents (such as taking drugs, the nature of work, etc.), The mother's pregnancy history, the birth history of the child, etc., in addition to various physical and chemical, biological factors on the embryo and the fetus.
2 Asking about family history and analyzing genealogy is one of the basic methods of genetic counseling.
3 According to the clinical manifestations, combined with the relevant laboratory tests, make a clear diagnosis, such as chromosomal abnormalities must be combined with karyotype analysis can be determined.
(4) Identify the genetic characteristics of each genetic disease: it is of great significance for guiding birth.
5. Prenatal diagnosis of prenatal diagnosis or intrauterine diagnosis is an important measure of preventive eugenics. The prenatal diagnostic techniques used are: 1 amniocentesis and related biochemical tests (amniotic puncture time is preferably 16 to 20 weeks of pregnancy) 2 pregnant women blood and amniotic fluid alpha-fetoprotein determination; 3 ultrasound imaging (applicable in about 4 months of pregnancy); 4X line examination (after 5 months of pregnancy), is beneficial for the diagnosis of fetal skeletal deformities; 5 staining of villous cells Quality determination (40 to 70 days of conception), predicting fetal gender to help diagnose X-linked genetic disease; 6 application of gene linkage analysis; 7 fetal microscopy.
Through the application of the above technology, the birth of a fetus with severe genetic diseases and congenital malformations is prevented.
Complication
Congenital testicular dysplasia complications Complications
Usually, the more X chromosomes, the more severe the mental retardation, and often accompanied by some trunk deformities such as cleft palate, cryptorchidism, and torticollis.
Symptom
Congenital testicular hypoplasia Symptoms Common symptoms Male sexual dysfunction Penile short testicular hypoplasia Breast hypertrophy Testicles Small sperm rare Male infertility No whisker hair and pubic hair
Patients with congenital testicular hypoplasia have no abnormalities in childhood, often abnormal during puberty or adulthood. The patient has a taller body, slender lower limbs, fine skin, pubic hair and whiskers, and often no bristles. About half of the patients have hypertrophy on both sides of the breast. The external genitalia is usually normal male, but the penis is shorter than normal males. The testicles on both sides are significantly smaller, less than 3cm, hard texture, poor sexual function, no sperm in semen, patients often do not The function of education or sexual function is low, and the mental development is normal or slightly lower.
Examine
Congenital testicular hypoplasia
1. Determination of serum testosterone (T): Most cases were reduced. According to statistics, 47% of patients with 47,XXY type decreased, 33% of patients with 46,XY/47,XXY type,48,XXXY,49,XXXYY and 49, Almost all of the XXXXY patients were reduced, generally with mild reduction, and severe reduction was rare.
2. Serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) determination: serum: FSH water increased, no overlap with normal people, serum LH levels, 47,XXY patients increased by 75%; 46, XY / 47, XXY patients increased by 33%; 48, XXXY, 49, XXXYY and 49, XXXXY patients increased the majority.
3. Determination of serum estradiol (estrodiol, E2): Most cases increased, and the increase in male breast development was more obvious.
4. Determination of serum androgen binding protein (ABP): Most have increased to varying degrees.
5. Human chorionic gonadotropin (HCG) test: The response of serum T to HCG stimulation is reduced or normal, and most of them are reduced to varying degrees.
6. Gonadotropin-releasing hormone (GnRH) test: Serum LH and FSH often respond strongly to GnRH stimulation.
7. Sexual chromatin examination: Oral mucosa scraping examination, where the chromatin (Barr body) with 2 or more X chromosomes is positive.
8. Semen examination: Most cases are azoospermia or sperm, but a small number of patients with 46, XY/47, XXY type semen examination can be basically normal.
9. Chromosome examination; peripheral blood lymphocytes are generally taken for karyotyping.
Testicular biopsy: typical histological signs are hyaline degeneration of the seminiferous tubules, lack of spermatogenic cells or significantly reduced, Leydig cells proliferating, may be pseudo-adenoma-like or nodular hyperplasia.
Diagnosis
Diagnosis and diagnosis of congenital testicular hypoplasia
It is generally difficult to make a diagnosis before the developmental period. Infertility or sexual dysfunction is the main reason for the patient's visit. The body type is higher, the bilateral testes are smaller, and the breast hypertrophy on both sides is a typical condition. The X body is positive and the karyotype is 47. , XXY can definitely diagnose.
The disease often needs to be differentiated from hypogonadotropic hypogonadism (HH). The latter testicle is small and soft, and the external genitalia and secondary sexual characteristics are poorly developed. The male breast development is less common and the body is smaller. High, upper and lower limbs are too long, plasma gonadotropin is reduced, serum T is significantly reduced, seminiferous tubules and Leydig cells are abnormal, karyotype is normal, according to these different characteristics can be distinguished from the disease.
