chromosomal anomalies

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

2. z Classification of
Genetic disorder
Single gene
disorders
Chromosome
Disorder
Autosomal
Numeric Structural
Sex chromosome
Numeric Structural
Multifactor
disorder
Acquired
somatic Genetic
disease

3. z
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.

4. z
Chromosome
affected
Autosomes
Numeric
Autosomal
Trisomies
Autosomal
Monosomy
Structural
Deletions
Sex
chromosomes
Numeric Structural
1.Cri du chat
syndrome
2. Prader Willi
syndrome
3. Angelman
syndrome

5. z
Autosomal
anomalies (
NUMERIC)
Monosomy
Single copy of
an autosome,
Lethal inearly
pregnancy
Trisomy
DOWN syndrome
(47+ 21)
EDWARD’s syndrome
(47 + 18)
PATAU syndrome
(47 + 13)

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

7. z
SKELETAL ABNORMALITIES (70%)

8. z
CNS ABNORMALITIES (70%)

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

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

11. z
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

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

13. z
Single umbilical
artery (80%)

14. z
CNS anomalies: (70%)
DOLICHOCEPHALY

15. z

16. z
Skeletal abnormalities:

17. z
Markers :
 Reduced materanal serum alpha fetoprotein
 Reduced Estriol
 Reduced beta HCG

18. z
DOWN SYNDROME:
 CONGENITAL HEART DISEASE:
 AVSD
 ASD
 VSD
• RESPIRATORY:
• Pulmonary hypoplasia
• Pulmonary cysts

19. z
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

20. z

21. z MUSCULOSKELETAL

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

23. z
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

24. z
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,
bridge
 Newborns also have microcephaly and have an increased risk of asphyxia

25. z
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

26. z Sex
chromosomes
Numeric
Autosomal
monosomy
Turner’s
syndrome
(45 XO)
Autosomal
trisomies
Klinefelter’s
syndrome
47 XXY
Jacob’s
syndrome
(47 XXY)
Triple x
syndrome
(47 XXX)
Structural
X linked
dominant
1.Alport
syndrome
2.Nephrogenic
DI
3. Hypo-
phosphatemic
rickets
X linked
Recessive
1. Colour
blindness
2. Duchenne
muscular
dystrophy
3.Hemophilia

27. z
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

28. z
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

29. z
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

30. z
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

31. z Radiological features:
 Skeletal features -> inconstant and non specific
 Decreased density of the skeleton ( esp . Hands and feet )
ANTENATAL ULTRASOUND
1. Cystic hygroma
2. Increased nuchal thickness
3. Increased nuchal translucency
4. Hydrops fetalis
5. Mild IUGR
6. Short fetal limbs

32. z
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

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

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

35. z 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

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

37. z
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

38. z
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

39. z
Cardiovascular defect

40. z
Pelvic ultrasound

41. z
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

42. z
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

43. z
Chromosome
affected
Autosomes
Numeric
Autosomal
monosomy
Autosomal
Trisomies
Patau syndrome
Edward syndrome
Down syndrome
Structural
Deletions
1.Cri du chat
syndrome
2. Prader Willi
syndrome
3. Angelman
syndrome
Sex
chromosomes
Numeric
Autosomal
monosomy
Autosomal
trisomies
1. Klinefelter’s
syndrome
2. Jacob’s
syndrome
3. Triple x
syndrome
Structural
X linked
dominant
X linked
recessive
1.Alport
syndrome
2.Nephrogenic DI
3. Hypo-
phosphatemic
rickets
Turner’s
syndrome
(45 XO)
1. Colour
blindness
2. Duchenne
muscular
dystrophy
3.Hemophilia
SUMMARY

44. z
 THANK YOU