GENETIC DISORDERS.pptx pathology genetic malformations

pathology genetic disorder

1. GENETIC DISORDERS

2. CHROMOSOME DIVISION

3. CHROMOSOME

4. KLINIFELTER SYNDROME It is defined as male hypogonadism that occurs when there are two or more X chromosomes or one or more Y chromosome. It is one of the genetic disease involving in the sex chromosome and cause of hypogonadism in the male. It can rarely diagnosed before puberty, because testicular abnormality does not develop before puberty.

5. The classic pattern of Klinefelter syndrome is associated with a 47,XXY karyotype. This is due to the nondisjunction during the meiotic division in one of the parents, mainly in Maternal first meiotic division. Klinefelter syndrome have been found to have a variety of mosaic pattern, most of them being 47,XXY/48,XXXY or 49,XXXXY karyotypes.

6. COMPLICATIONS Increase in length between the soles and the pubic bone(elongated body) Small atrophied testes associated with small Penis. Lack of secondary sexual characteristics -deep voice -Beard -Pubic hair distribution

7. Low IQ level Reduced spermatogenesis and male Infertility. Presence of Gynecomastia. Increased FSH level Increased estradiol level

8. Ratio between estrogen and testosterone determines the degree of feminization in individual. The testicular tubules are totally atrophied and replaced by pink, hyaline, collagenous substances. In some cases ,testicular tubules are interspersed with atrophic tubules. In others, all tubules are primitive and embryonic consisting of cords of cells that never developed a lumen or progressed to mature spermatogenesis.

9. STRUCTURE OF TESTES

10. TURNER SYNDROME

11. TURNER SYNDROME Turner syndrome results from complete or partial monosomy of X chromosome and is characterised primarily by hypogonadism in phenotypic females . 57% are missing an entire X Chromosome ,resulting in 45,X karyotype. 14% have structural abnormal X chromosome. 29% are mosaic.

12. Structural abnormalities of X chromosome includes Deletion of the small arm, resulting in the formation of an isochromosome of the long arm,46X,i(X)(q10) Deletion of portion of both long arm ,46X,r(X) Deletion of the short or long arm,46X,del( xq ) or 46X,del( Xr ) The mosaic patients have a 45X cell

13. COMPLICATIONS Oedema of the hand and foot, Swelling of the nape of neck. Cystic hygroma(elongated lymph channel). Bilateral neck webbing Looseness of skin on the back of the neck Congenital heart disease-Preductal coarctation of aorta and Bicuspid aortic valve

14. CLINICAL FEATURES Failure to develop normal secondary sex characteristics Genitalia remain infantile Inadequate breast development Little pubic hair Shortness of stature Amenorrhea

15. Approximately,50% of patient develop autoantibodies directed to the thyroid gland and manifestation of hypothyroidism .Mechanism is unknown. In some patients, presence of glucose intolerance, obesity and insulin resistance occur.

16. In Turner syndrome, foetal ovaries develop normally early in embryogenesis ,but the absence of the second X chromosome leads to an accelerated loss of oocytes , which is complete by the age of 2 years. Menopause occur before menarche. Ovaries are reduced to atrophic fibrous strands, devoid of ova and follicles(streaky ovaries).

17. DOWN SYNDROME

18. DOWN SYNDROME/TRISOMY 21 Trisomy  result from  chromosomal non-disjunction of chromosome 21 (47,XX,+21 or 47,XY,+21)  at conception. The most common cause of Down syndrome is meiotic non disjunction. Maternal age  has strong influence on trisomy21 . This chromosomal disorder is the common cause for mental retardation. 95% of affected individual have Trisomy21,their chromosome count is 47.

19. CLINICAL FEATURES Flat face Oblique palpebral fissures Epicanthic fold Severe mental retardation(IQ 25 TO 50) Congenital heart disease(Atrial /ventricular septal defect ,Atrioventricular valve defects)

20. Atresia of esophagus and small bowel. Alzheimer disease Cell mediated immune disturbance

21. ESOPHAGEAL ATRESIA

22. INTESTINAL ATRESIA