chromosomal anomalies.pptx

chromosomal anomalies

1. CHROMOSOMAL ANOMALIES Dr. Niranjan patil Department of Radiodiagnosis DYP Kolhapur

2. CHROMOSOMAL ANOMALIES Chromosomal anomalies = Missing , extra or irregular portion of chromosomal DNA Chromosomal anomalies are detected via karyotype testing Abnormalities depends on type of chromosome affected due to non- disjunction chromosomes.

3. 1.Cri du chat syndrome 2. Prader Willi syndrome 3. Angelman syndrome

4. NUMERIC AUTOSOMAL ANOMALIES PATAU syndrome: Abnormal facies: 90%, strong marker Cleft lip +/- palate Micropthalmia Micrognathia Hypotelorism/hypertelorism Cyclopia proboscis

5. SKELETAL ABNORMALITIES (70%)

6. CNS ABNORMALITIES (70%)

7. CONGENITAL HEART DISEASE (50-70%) GENITOURINARY ANOMALIES

8. ABDOMINAL WALL ABNORMALITIES MARKERS: Reduced maternal serum AFP Reduced maternal beta HCG Reduced PAPP-A

9. Antenatal ultrasound: general features Intrauterine growth restriction (IUGR) tends to be early Abnormal liquor volume : mostly polyhydramnios or oligo Increased nuchal thickness Evidence of hydrops fetalis

10. EDWARD SYNDROME: CONGENITAL HEART DISEASE (90-95%)

11. Single umbilical artery (80%)

12. CNS anomalies: (70%) DOLICHOCEPHALY

13. Skeletal abnormalities:

14. Markers : Reduced materanal serum alpha fetoprotein Reduced Estriol Reduced beta HCG

15. DOWN SYNDROME: CONGENITAL HEART DISEASE: AVSD ASD VSD RESPIRATORY: Pulmonary hypoplasia Pulmonary cysts

16. CNS MANIFESTATIONS: Intellectual disability : avg IQ 50-70% Hearing loss from inner ear anomalies ( eg. Semicircular canal dysplasia and dehiscence, narrowed internal acoustic canal , cochlear nerve canal stensosis ) Cerebellar and vermian hypoplasia Alzheimer disease developing in all patients older than 40 yrs

17. MUSCULOSKELETAL

18. In the postnatal period, characteristic  phenotypical  features point to the diagnosis:

19. MARKERS: Reduced materanal serum alpha fetoprotein Reduced Estriol Reduced beta HCG PATAU SYNDROME EDWARD SYNDROME DOWNS SYNDROME Reduced maternal serum AFP Reduced maternal beta HCG Reduced PAPP-A Reduced materanal serum alpha fetoprotein Reduced Estriol Reduced beta HCG Maternal free  beta-hCG : higher than chromosomally normal fetuses inhibin A: higher than chromosomally normal fetuses AFP: lower than chromosomally normal fetuses   unconjugated estriol (uE3): lower than chromosomally normal fetuses  

20. STRUCTURAL AUTOSOMAL ANOMALIES : CRI DU CHAT SYNDROME Cri du chat syndrome  is a rare congenital disorder caused by the deletion of the short arm of chromosome 5. A high-pitched monotonous cry is the characteristic finding. The patient also usually has craniofacial malformations such as  microcephaly, hypertelorism, large nasal bridge Newborns also have microcephaly and have an increased risk of asphyxia 

21. Prader-Willi and Angelman Syndrome Prader-Willi Syndrome Microdeletion of chromosome15 Lack of muscle tone in newborn As adult – gross obesity Radiographic features: Abnormalities of calvarium and sella turcica Coxa valga Scoliosis Angelman Syndrome Microdeletion of chromosome 15. Development delay Jerky movements Stiff, fixed smile Epilepsy

22. Klinefelter syndrome Childhood: Weaker muscles and reduced strength Puberty: Tall stature ; long lower limbs, Rounder body type Testicular atrophy/ Microorchidism ( small testicles) Female pattern of pubic hair Gynecomastia( increased breast tissue) Azospermia leading to infertility Micropenis IQ is normal Serum testosterone levels low to normal FSH and LH levels very high

23. Radiographic features: USG: Klinefelter   syndrome should be suspected in postpubertal males with bilateral symmetrical small testicular volume (usually 3~4 mL in volume) usually presented by subfertility/primary infertility or assessment of small testicular size

24. TURNER SYNDROME Absence of one chromosome x (45 XO ) Most common sex abnormality in females GENE SHOX -> important for bone development and growth Loss of one copy of this gene -> short stature

25. Clinical Findings Normal intelligence Ovaries develop normally at first but oocytes die prematurely and most ovarian tissue degenerate before birth Heart defect ( coarctation of the aorta, abnormalities of aortic valve ) Short stature -> becomes evident by about age 5 Webbed neck

26. Radiological features: Skeletal features -> inconstant and non specific Decreased density of the skeleton ( esp . Hands and feet ) ANTENATAL ULTRASOUND Cystic hygroma Increased nuchal thickness Increased nuchal translucency Hydrops fetalis Mild IUGR Short fetal limbs

27. Nuchal translucency INCREASED nuchal translucency A finding during first trimester Measured on saggital image through the fetal neck Rate of aneuploidy when the nuchal thickness is < 2mm - -> less than 1 % Back of neck

28. Nuchal thickness: INCREASED nuchal thickness Measured in a second trimester Abnormal value > 6mm Should not be measured after 20.6 weeks Back of head

29. Cystic hygroma A cystic lymphatic lesion Septation indicate poorer outcome Volumes > 75mm3 correlate with increased abnormality and poorer fetal outcome

30. Hydrops fetalis Excessive accumulation of fluid in fetal subcutaneous tissue or atleast 2 fetal serous cavities Fetal pleural effusion Fetal pericardial effusion Fetal ascites Placental enlargement Polyhydromnios Fetal anasarca

31. Hand and feet : Post partum and Adulthood HAND: Positive metacarpal sign Increased carrying angle of elbow / cubitus valgus. FEET: Abnormal medial tibial condyle -> depressed and beak like Abnormal medial femoral condyle -> project downward

32. Positive metacarpal sign A line drawn along the heads of 4 th and 5 th metacarpals will intersect the head of the 3 rd metacarpal if shortening is present

33. Cubitus valgus Increased carrying angle of the elbow Carrying angle ( Cubital angle ) -> formed between the humerus and the forearm axis NORMAL – 5-15 degree away from the body <5 degree : cubitus varus >15 degree: cubitus valgus

34. Cardiovascular defect

35. Pelvic ultrasound

36. Dd TURNER’S SYNDROME DOWN SYNDROME Normal intelligence Mental retardation Cardiac defect : coartation of aorta, bicuspid aortic valve Cardiac defect: intracardial septal defect Metacarpal sign Cubitus valgus Clinodactily Mickey mouse pelvis ( large ilium) Absence of last rib Webbed neck Orbital hypo/ hypertelorism Cystic hygroma Increased Nuchal thickness Increased Nuchal translucency Cystic hygroma Increased Nuchal thickness Increased Nuchal translucency

37. GENOTYPE GENDER SYNDROME PHYSICAL TRAITS XY MALE - XXY MALE Klinefelter’s syndrome Sterility, small testicles, breast enlargement XYY MALE Jacob’s syndrome Normal male traits XX FEMALE - XO FEMALE Turner syndrome Sex organs don’t mature at adolescence , sterility, short stature XXX FEMALE Triple X Tall stature , normal intelligence with learning disabilities, limited fertility

38. SUMMARY

39. THANK YOU