| There is about 15% couples can't gestate at there child-bearing age, the etiological factors include: structural disease, endocrine secretion disease, nerves factor, immune factor, genetic factor, infection, and so on. At present, the diagnosis about these patients focus on hormone level, immunologic test, cytogenetic test, molecular genetic test is not used as a routine control method. Among these patients who have dysplastic secondary sex characteristics, Kallmann syndrome is an important origin. Kallmann syndrome (KS) is a rare hereditary disease, characterized by hypogonadotrophic hyponadism in association with anosmia or hyposmia, affects an estimated 1 in 10,000 men and 1 in 50,000 women. As a genetic disorder, KS occurs in both sporadic and inherited forms. At present, three modes of inheritance and gene related to KS have been identified; inherited forms include autosomal dominant, autosomal recessive, and X-linked recessive transmission patterns. The pathogenesy of KS is the mutations in related genes, which lead to the abnormal secretion of GnRH in regions of the brain outside of the Hypothalamus.Nowadays, there are many cyto-molecular biology methods for us to diagnose inherited diseases. With chromosome G-banding, we can find apparente chromosome aberration; FISH and multiple PCR help us to find minute deletion of chromosome. Among these patients with dysplastic secondary sex characteristics caused by genetic factors, Kallmann syndrome takes a considerable part. For the past few years, along with the consideration of this disease, the disease rate is about to rise. Most of these KS patients came to hospital for dysplastic secondary sex characteristics, barrenness and sexual disturbance. Clinical symptom and gonadal hormone level are used mostly in diagnosis and therapy of KS. The curative effect of KS patients depends on the early diagnosis, the earlier the disease is definite, the better curative effect they will get. So, it's very critical to take gene tests in these teenagers with dysplastic secondary sex changes.Objective: From March 2008 to February 2009, there are 1357 people came to have chromosome test because of infertility. According to their secondary sex characteristics, especially teenagers'sex character, we choose and save 29 samples of them to study. All of them were male with the sex chromosome karyotypes 46 XY and had the character of hypogonodotropic hypogonadism, anosmia and part of them with low level of serum FSH, LH, and testosterone. We made multi-PCR and FISH tests to find if there is some relationship between the teenagers'dysplastic sex character and KAL-1 gene mutation, in order to provide some consultation for the diagnosis, treatment and research.Methods: In accordance with the principle of informed consent from the patients with peripheral blood, cultivate peripheral blood lymphocytes to gain G-banding karyotype analyses and prepare a cell suspension, for multiple PCR and FISH. We also scraped some cell remain from G-banding glass slide for PCR as there is no cell suspension left.Results: There are 3 cases of the 29 cases we collected have mutation in KAL-1 gene, the mutation rate is 10.2%. We found two polymorphic changes in the KAL-1 gene with 3 patients, two of which are full brothers, one is sporadic. These polymorphisms were: one exon 2 deletion; two exons 5~ 9 deletions. FISH results is in accordance to the PCR results, the one who lost exon 2 is FISH (+), the two who lost exons 5~9 is FISH (-).Conclusion: The mutation rate in our research is 10.2%, much higher than the normal rate reported in related literature. It's relevant to the research group we choosed. Spontaneous pubertal development and secondary sex character had failed in all the three patients who have mutations in KAL-1 gene. So, for teenagers who have ataxinomic secondary sex character, it's necessary and important to take KAL-1 gene analysis. The molecular genetics analysis means is very useful for clinical diagnosis and treatment of Kallmann syndrome.
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