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nt and aneuploidy

nt and aneuploidy. . Monosomics for all human autosomes die in utero. A sex-chromosome monosomic complement of 44 autosomes + 1 X produces the phenotype of Turner syndrome.

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nt and aneuploidy

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  1. nt and aneuploidy

  2. . Monosomics for all human autosomes die in utero. A sex-chromosome monosomic complement of 44 autosomes + 1 X produces the phenotype of Turner syndrome. The most common type of viable human aneuploid is Down syndrome occurring at a frequency of about 0.15 percent of all live births The only other human autosomal trisomy to survive to birth are afflicted with either trisomy 13 (Patau syndrome) or trisomy 18(Edwards syndrome). Trisomies chromosome 2, 16, and 22 are relatively common in abortuses but never survive to birth. Trisomy of the sex chromosomes is possible, such as in (47,XXX), (47,XXY), and (47,XYY).

  3. NUCHAL TRANLUCENCY

  4. NT - MOST ROBUST MARKER • NASAL BONE • TRICUSPID FLOW • DUCTUS VENOSUS FLOW Usg markers

  5. COMBINEDSCREENING MA+NT+BIOCHEMICAL MARKERS  Advantages compared to second trimester biochemical screening  include: Earlier diagnosis (11-14 weeks) Higher detection rates  for fetal Down syndrome (80-90% or perhaps even higher compared to 75% for the second trimester "quad" screen and 60-70% for the older "triple" screen) Detection of most major chromosome abnormalities other than trisomy 21 Acts as a nonspecific marker for other birth defects  including some major cardiac defects and syndromic conditions Can detect a number of major structural birth defects associated with normal chromosomes The primary disadvantage is Narrow window of entry (11-14 weeks with ideal entry at 11-12 weeks). WHY FIRST TRIMESTER

  6. MATERNAL AGE + NT M A + NT + BIOCHEMICAL MARKERS M A + NT + B M + NB/DV FLOW/TCV FLOW. RISK 1 TO 50 NB –N NO CHANGE IN RISK RISK UPTO 1 TO 1000 NB- N RISK REDUCED NB-AB RISK INCREASED HYPOPLASTIC NB ALL OTHER MARKERS N –REPEAT SCAN REVERSE a WAVE RISK ALWAYS INCREASED NT AND ANEUPLODY

  7. INCREASED NT A/W INCREASED FETAL MORTALITY INCREASED NT A/W STRUCTURAL ABNORMALITIES MAJOR CARDIAC DEFECTS DIAPHRAGMATIC HERNIA EXOMPHALOS SKELETAL DEFECTS BODY STALK ANOMALIES NT AND EUPLOID FETUS

  8. I Fetal abnormalities The 11-14 week scan

  9. Normally nuchal translucency disappears by 14 weeks. Noteworthy are cases with abnormal NT that resolve spontaneously around 14 weeks and show healthy outcome Chromosomally and structurally normal fetuses with history of thickened NT with no evidence of nuchal fold thickening or non-immune hydrops, at 20 weeks -- no increased risk for perinatal or long-term morbidity and mortality ABNORMAL NT NORMAL FETUS

  10. Chromosomally and structurally normal fetuses with • Altered dermal collagen composition (eg, Down syndrome) • Abnormal nuchal lymphogenesis (eg, Turner syndrome) • Hemodynamic alterations and cardiac dysfunction( heartdefects) • Abnormal endothelial cell differentiation Pathophsiology of NT-

  11. ABSENT PRESENT Nasal bone

  12. NORMAL REDUCED INCREASED TRISOMY 21 MAXILLO FACIAL ANGLE

  13. reverse a wave a/w chromosomal defects cardiac defects and adverse fetal outcome DUCTUS VENOSUS FLOW

  14. Prevalence of TCV regurgitation in fetuses with trisomy 21 is about 74% whereas only 7% of chromosomally normal fetuses have this finding There is an increased prevalence of cardiac defects with TC regurgitation, irrespective of the presence or absence of aneuploidy Tricuspid flow

  15. FETAL GROWTH/ CRL - REDUCED GROWTH CAN BE SEEN IN TRISOMY 13 ,18, TURNERS SYNDROME HOWEVER NOT IN TRISOMY 21 FETAL HEART RATE -BRADYCARDIA SEEN IN TRISOMY 18 AND TRIPLOIDY AND TACYCARDIA IN TRISOMY 13 AND TURNER SYNDROME FETAL MEASUREMENTS AS MARKERs

  16. SINGLE UMBILICAL ARTERY/ TWO VESSEL CORD SEVEN FOLD INCRESED RISK FOR TRISOMY 18 FETAL STRUCTURAL DEFECTS AS MARKERS

  17. MEGACYSTIS LONG. BLADDER OF >7MM 7-15 MM A/W INCREASED RISK OF TRISOMY 13 AND 18 EUPLOID FETUSES –SPONTANEOUS RESOLUTION >15 MM LESS LIKELY CHROMOSOMAL ANOMALIES MORE LIKELY TO CAUSE OBSTRUTIVE UROPATHY megacystis

  18. HIGH ASSOCIATION WITH TRISOMY 18 ONE OF THE REASONS TO PERFORM NT SCREENING AT 11WEEKS NO PHSIOLOGICAL BOWEL HERNIATION OMPHALOCOELES WITH ONLY BOWEL HERNIATION STRONGER ASSO. WITH ANEUPLOIDY Aneuploid fetuses with omphalocoeles containing only bowel show resolution in significant no of fetuses, most likely developmental delay. OMPHALOCOELE

  19. EXTREME FORM ALOBAR HOLOPROSENCEPHALY CAN BE DETECTED IN FIRST TRIMESTER INCREASED RISK OF ANEUPLOIDY MOSTLY TRISOMY 13 HOLOPROSENCEPHALY

  20. THE FIRST TRIMESTER SCAN IS NO LONGER A NT SCAN BUT A FETAL ANATOMY SCAN The first trimester anomaly scan detectable abnormalities

  21. INTRACRANIALTRANSLUCENCYIN OPEN NEURAL TUBE DEFECTS The fourth ventricle presents as an intracranial translucency (IT) between the brain stem and the choroid plexus. a case of open spinabifid demonstrating compression of the fourth ventricle with no visible translucency.

  22. Arnold chiari 2 Lemon sign: Scalloping of frontal bones Banana sign: Caudal displacement of cerebellum , obliteration of CM Not consistently seen in first trimester.

  23. NORMAL POST FOSSA CYST OPEN SPINA B Posterior fossa at 11 to 13.6 weeks

  24. Meningoenc • Occipital (MC) – A/w skull defect (cf D/D Nuchal cystic hygrom • ParietalFrontoethmoidal A/w Microcephaly, Hydrocephalus, Spina bifida, Meckel Gruber Syn. Neural Tube Defects d/d : Cystic Hygroma

  25. SKULL OSSIFICATION AT 11 WEEKS OF OCCIPITAL BONE Varying degrees of distortion of brain ACRANIA–exencephaly-Anencephaly

  26. Encephalocoele Polycystic kidneys Polydactyly MeckelGruber Syndrome

  27. Complete or partial absence of cerebellar vermis 4th Ventricle Dilatation End point of chromosomal abn. , Genetic Syndromes , congenital infection or Isolated abn DANDY WALKER COMPLEX

  28. Total absence of cerebral hemispheres • Large head • Small hemispheres • Fluid-filled intracranial cavity with no midline echoes Hydranencephaly

  29. Alobar and Semilobara/w facial abnormalities Lobar Holoprosencephaly

  30. Rare Cervical dysraphism with occipital(inion) defect +encephalocoele Persistently extended fetal head -clue Iniencephaly

  31. Fetal 4 chamber view can be demonstrated at 11to 14 weeks scan RAISED NT PERSISTENT BRADYCARDIA (60BPM) COMPLETE AV CANAL DEFECT A 14 WEEK SPECIALIST SCAN CAN REVEAL MAJOR ABN OR RAISE SUSPICION FOR LATER DETAILED SCAN Cardiac anomalies

  32. AV CANAL DEFECTS VSD 4 CHAMBER VIEW

  33. CAUDAL REGRESSION SYNDROME DEGREES OF VERTEBRAL ANOMALIES FROM PERTIAL SACRAL AGENESIS TO ABCENCE OF LUMBAR SPINE. 250 TIMES MORE COMMON IN POORLY CONTROLLED DIABETIC MOTHERS ABSENT LIMBS MUSCULOSKELETAL ABN.

  34. PHSIOLOGIC BOWEL HERNIATION AT 9 TO 11 WEEKS EXOMPHALOS - a/w CHROMOSOMAL DEFECTS .CORD INSERTION AT APEX OF SAC VS GASTROCHISIS PARA MIDLINE HERNIA SAC BODY WALL ANOMALIES

  35. PYELECTASIS RANGE MEGACYSTIS CYSTIC DYSPLASTIC KIDNEY RENAL AGENESIS POLYCYSTIC KIDNEYS URINARY ANOMALIES

  36. SECOND TRIMESTER FETAL ANOMALY

  37. Fetal cardiac examinations optimally performed between 18-22 weeks. Some anomalies may be identified in late first and early second trimester especially when increased nuchal translucency is identified. 4 chamber view, 3 vessel view and outflow tracts can detect 80% -85% of cardiac anomalies CARDIOVASCULAR ANOMALY

  38. BASIC VIEW four chamber view

  39. EXTENDED BASIC VIEWS Left ventricular outflow tract(LVOT) Right ventricular outflow tract(RVOT)

  40. One of the most common congenital cardiac anomaly VSD is easily diagnosed on the four-chamber view alone. However, color Doppler US may be needed to demonstrate smaller defects and some may not be detected until after birth. Small VSD (MUSCULAR)show spontaneous closure VSD

  41. When the endocardial cushions fail to fuse, a wide range of atrioventricularseptal defects occur. ENDOCARDIAL CUSHION DEFECT (four-chamber view) shows absence of the interventricular and interatrial septa, thus producing connections between the ventricles and between the atria.

  42. The undivided truncus receives blood from both ventricles. A VSD is almost always present PERSISTENT TRUNCUS ARTERIOSUS a.(four-chamber view) shows a VSD (arrow). Dao descending aorta. b.(base view) shows a single trunk (arrow) overriding both ventricles.

  43. Small left ventricle, which is associated with aortic atresia. Atretic or hypoplastic mitral valve. HYPOLPASTIC LEFT HEART SYNDROME Hypoplastic left heart syndrome in a fetus (four-chamber view) shows that the left ventricle is small relative to the right ventricle and the left atrium is small relative to the right atrium.

  44. CAUDALLY PLACED TRICUSPID VALVE /OFFSET BETWEEN MITRAL AND TRICUSPID VALVE /ENLARGED RT VENTRICLE /TRICUSPID REGURGITATION EBSTEIN ANOMALY

  45. PARALLEL OUTFLOW TRACTS , LARGE RT VENTRICLE ,SMALL LT VENTRICLE DOUBLE OUTLET RIGHT VENTRICLE

  46. NORMAL HEART RATE 2ND IS 120BPM TO 160BPM FETAL ARRYTHMIAS  can now be defined precisely for mechanism-specific therapy and for subsequent monitoring of response. RHYTHM AMNORMALITIES OF HEART

  47. FETAL SKELETAL STRUCTURES TO BE SEEN: FETAL CRANIUM(BPD, HC) ABDOMINAL CIRCUMFERENCE(AC) MANDIBLE CLAVICLE SCAPULA CHEST CIRCUMFERENCE ALL FETAL LONG BONES( RHIZOMELIA, MESOMELIA, MICROMELIA) FETAL FACIAL PROFILE(GLABELLAR BOSSING, FLATTENED NASAL BRIDGE, MICROGNATHIA) VERTEBRAL BODIES HAND AND FEET( EXTRA/MISSING/MALFORMED DIGITS) MINERALISATION PATTERN. CHEST:ABDOMEN CIRCUMFERENCE( <0.6 ABNORMAL) FL:AC RATIO(<0.16 ABNORMAL) FL: FOOT LENGTH RATIO(<1 ABNORMAL) MSK ANOMALIES

  48. FETAL LONG BONES: PRESENCE/CURVATURE/MINERALISATION/FRACTURES The femur length–abdominal circumference ratio (<0.16 suggests lung hypoplasia) femur length–foot length ratio(normal = 1, <1 suggests skeletal dysplasia) THORAX: CHEST CIRCUMFERENCE/ CT RATIO MEASURED AT THE LEVEL OF FOUR CHAMBER VIEW OF HEART. HAND AND FEET: PRE AND POSTAXIAL POLYDACTYLY/SYNDACTYLY/CLINODACTYLY/OTHER DEFORMITIES SKULL:HC/BPD/SHAPE/MINERALISATION/OSSIFICATION. FACIAL STRUCTURES:MICROGNATHIA/ SHORT UPPER LIP/ABNORMALLY SHAPED EAR/FRONTAL BOSSING/CLOVERLEAF SKULL. PELVIS: HYPOPLASTIC ACETABULAE/FLAT ILIAC BONES. CONTD..

  49. LIMB DEFICIENCY: complete absence –amelia, incomplete absence-meromelia. FETAL SKELETAL DYSPLASIA lack of a normal hand and the abnormal soft tissue at the distal end of the forearm

  50. Disproportionate dwarfism with very short extremities,which are bowed in type 1 and may be straight in type 2. Thorax is narrow. Cloverleaf skull deformity is generally seen in type 2. Polyhydramnios is present in almost 50% of cases. Pulmonary hypoplasia. THANATOPHORIC DYSPLASIA telephone receiver–shaped femur hypoplastic thorax

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