OSCE - GENETIC..........................

OSCE PEDIATRICS
GENETICS
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Spot 1
 Identify the pattern of inheritance
 Name 3 conditions with similar inheritance
 What is the degree of inheritance?
 Which sex is affected ?

 Autosomal dominant
 NF1 , Polycystic kidney disease
,tuberous sclerosis , hereditory
spherocytosis,marfans syndrome,
osteogenesis imperfecta.
 50%
 Either sex.

Spot 2
 39 year old female, 10 weeks pregnant, is concerned
about Downs Syndrome . Which antenatal tests will
you advise?
 Name some other antenatal markers used?
 If mother is a translocation carrier, how much is the
risk to the offspring ?
 Name the associated chromosomes with tranlocation?
 Recurrence risk is highest with which translocation ?

 Chorionic villi sampling[10-12 wk],
amniocentesis[16-20 wk ],cordocentesis [20
wk]
 Triple test [2nd trimester]-low Serum alpha
feto protein, low unconjugated estradiol, high
levels of human chorionic gonadotropin.Fetal
USG-Increased nuchal fold thickness,short
femora.
 10-15 %
 14,15,21,22
 21q/21q [100%]

Spot 3
 Identify the syndrome and State the chromosomal
anomaly
 What is the phenotype in this syndrome ?
 Mention the cardinal features of the syndrome
 Any easy outpatient OPD procedure for the diagnosis
?
 What’s the male version ?

 Turner syndrome
 45 XO
 Female
 Short stature, broad chest with wide
spacing of nipples,congenital
lymphedema,webbed neck,hyperconvex
nails ,ovarian dyegenesis,cubitus
vulgus,short fourth metacarpel,horse
shoe kidney,bicupid aortic valve
 Buccal smear for barr body
 Noonan syndrome

 Which syndrome has this genotype ?
 What is the phenotype ?
 State associated salient features.
Spot 4

 Klinefelter syndrome
 Male
 Hypogenitalism ,hypogonadism ,tall stature
,mental retardation and behavior concerns-
aggressive behavior, antisocial acts, learning
difficulties, anxiety

 Male child with
mental retardation,
 identify the syndrome
 What is the exact locus?
 What is pattern of inheritance ?
 Mention any another syndrome
with similar inheritance
Spot 5

 Fragile X syndrome
 Xq 27.3
 Allelic expansion-change in the increasing size
of a particular DNA sequence from generations
to generations
 Huntington disease, spinocerebellar
ataxia, myotonic dystrophy, DRPLA[dentato
rubro pallido luysian atrophy]

 Identify the pattern of inheritance
 Name 3 conditions of similar inheritance
 Which is the affected sex ?what is the risk
of getting affected in each pregnancy ?
Spot 6

 X – linked recessive
 Hemophilia , color blindness , G6PD
deficiency , DMD, menkes kinky hair
disease, adrenoleukodystrophy
 Male ,the risk is 50% for male child in each
pregnancy.

 Identify the syndrome
 Name the pattern of inheritance
 Give 1 another example of similar inheritance
 What will be the risk of inheritance to
offsprings in affected males with disease
Spot 7

 Incontinentia pigmenti
 X-linked dominant
 Hypophosphatemic rickets, OTC
deficiency, Alport disease
 All the daughters and none of the sons the
of an affected male have disease

 Identify the diagnostic technique
 Name 3 syndromes in which this technique
is used for diagnosis
Spot 8

 FISH
Fluorescent In Situ Hybridization
 Down syndrome
 Prader willi syndrome
 Angel man syndrome
 Williams syndrome
 Miller Dicker syndrome

 State 3 procedures for antenatal genetic
diagnosis ,also mention about the earliest
gestational age at which these tests can be
performed .
 What is the risk of fetal loss ?
 3 common diseases in which antenatal
diagnosis is available
Spot 9

 Amniocentesis –15-16 week of gestation
Chorionic villi sampling –10 12 wks
Cordocentesis –20 wks
Skin biopsy ,liver biopsy
Amniocentesis-0.5-1%
CVS- 1-2%
Down syndrome, DMD, SMA, Beta- Thalassemia
, turner syndrome, XXY

 Name 3 vectors used in gene therapy
 State 3 candidate diseases (with single gene
defects) for gene therapy
Spot 10

 Retrovirus ,adenovirus , adeno associated
virus , naked DNA
 Any chromosomal anomalies ,Severe
combined immunodeficiency,
Cystic fibrosis, hemophilia, PKU,
Gaucher disease, Beta- hemoglobinopathies

7 year male child with hypotonia and hypogonadism
 Identify the syndrome
and chromosome
involved
 Name the genetic
pattern of inheritance
 Which is the other
syndrome related to
the same chromosome
Spot 11

 Prader willi syndrome ,chromosome 15
 Genetic imprinting / uniparental dizomy
 Angelman syndrome

 Identify the
syndrome
 Which metabolic
problem these
children face ?
 Give three salient
features
 Mention the
chromosome
involved
Spot 12

 Beckwith-Wiedemann syndrome
 Hypoglycemia
 LGA, macroglossia, earlobe
crease, visceromegaly
 Chromosome 11p

Name 3 associated systems involved with 2
conditions in each.
A test you need to do prior to discharge from
hospital – at birth.
Spot 13

 Eyes – cataract, Brushfield spots, myopia,
nystagmus
 Cardiac – Endocardial cushion defect, VSD,
PDA,
 GIT – Duodenal atresia, annular pancrease,
TOF, Hirschsprungs
 Bone – AAD, CDH
 Endocrine – hypothyroid, athyroid
 CNS – delayed development, seizures,
 Thyroid assessment

 Diagnosis
 Name 5 types of
this condition
 What is the urinary
test for diagnosis
 Name 3
metabolites seen in
the urine
 Name the main
organs involved
 What are the Xray
findings called
Spot 14

 Mucopolysaccharidosis
 Hunter, Hurler, Scheie, Sanfillipo,
Matoteaux Lamy, Morquio, Sly
 Urine electrophoresis
 Dermatan, Keratan, Heparan sulphate
 liver, spleen, bone, cornea, hearing,
cardiac
 Dysostosis multiplex

 Diagnosis
 Inheritance
 Incidence of
next sib with
same problem
 Which sex is
involved
Spot 15

 Tuberous sclerosis
 Autosomal recessive
 25%
 Both, equal chances

 Name 3 drugs contraindicated in pregnancy
 Name 3 drug related syndromes with one
associated feature each.
Spot 16

 Alcohol, Warfarin, Valproate, Phenytoin, Methotr
exate, retinoic acid, Lithium
 Fetal alcohol – IUGR, Microcephaly, small
palprebal fissures
 Fetal Hydantoin – growth def., MR, finger and
nail abnormalities
 Fetal Valproate- Dysmorphisms, CVS –
coarctation, spina bifida
 Fetal Warfarin – nasal hypoplasia, stippled
epiphysis, hypoplastic distal limbs

•Diagnosis
•Name 2 more conditions with
•similar features
Spot 17

 Cockaynes syndrome
 Progeria, Wiedeman Syndrome, Werner
syndrome, Rothmund thompson

 Name the abnormality
 Name 2 syndromes with
this feature
 Which other organ
systems would you test
Spot 18

 Bilateral Cleft lip
 Trisomy 13, Cleft lip sequence, fetal
hydantoin, Holoprosencephaly, CHARGE,
Trisomy 18
 All midline structures
 CNS, Cardiac, renal, gonads, ophthal, nose,
umbilicus.

 Diagnosis
 Name 2 more
conditions with
such features
 2 organ systems
for testing
Spot 19

 Proteus syndrome, Maffucis, focal
Hemihypertrophy
 Maffucis, Klippel trenauney syndrome,
Proteus
 Skeletal, brain, skin, Growth, Visera,
Heamat, Vascular

 Diagnosis
 Direct Cause
 Underlying
pathology
 2 other tell
tale signs
Spot 20

 Club foot, eqino varus, amniotic band
sequence, arthogryposis sequence
 Decreased fetal movements in utero
 Congenital CNS/ PNS involvement mainly
nerve, muscle
 Umbilical hernia, undescended testes, weak
cry, poor respiration, dimples

47
2.1 PEDIGREE QUESTIONS
PEDIGREE QUESTION 1
1. Describe the pedigree.
2.What is the mode of inheritance?
3. Give 4 examples.
PEDIGREE QUESTION 2
1. What is the pattern of inheritance?
2. Name three conditions with similar pattern of inheritance.

48
PEDIGREE QUESTION 3
1. Identify the pattern of inheritance in the given pedigree with
explanation.
2. Explain the mechanism of this inheritance.
3. Give 2 examples of this pattern of inheritance.
PEDIGREE QUESTION 4
1. Identify the pattern of inheritance.
2. Name three conditions with similar inheritance.
3. What is the risk of getting affected in each pregnancy?

49
PEDIGREE QUESTION 5
1. What type of inheritance is shown?
2. What is the risk of recurrence in the next pregnancy?
3. Give 4 examples for this type of inheritance?

50
2.1 PEDIGREE ANSWERS
PEDIGREE ANSWER 1
1. 3 generation pedigree chart showing
All daughters of the affected males have the disease
Sons of the affected males are normal
Affected females affect ½ of the males and ½ of the
daughters
2. X- linked dominant inheritance
3.
Hypophosphatemic rickets ( Vit.D resistant)
Incontinentia pigmenti
Oro facial digital syndrome
Rett syndrome
PEDIGREE ANSWER 2
1. Autosomal dominant.
2. Neurofibromatosis type 1, polycystic kidney disease, tuberous
sclerosis,hereditary spherocytosis, Marfans syndrome,
osteogenesis imperfecta.
PEDIGREE ANSWER 3
1. Mitochondrial inheritance. All affected females have offspring
who suffer from the disease. Affected males do not transmit the
disease.
2. Mitochondrial DNA present in the ovum transmits the
characteristics to the offspring. Such DNA is not present in the
sperm.

51
3. MELAS (myopathy, encephalopathy, lactic acidosis, and
strokelike episodes), MERRF (myoclonic epilepsy associated with
ragged red fibers), and Kearns-Sayre syndrome (ophthalmoplegia,
pigmentary retinopathy, and cardiomyopathy)
PEDIGREE ANSWER 4
1. X-linked recessive.
2. Hemophilia, color blindness, G6PD deficiency, Duchenne
musculardystrophy, Menkes kinky hair disease,
adrenoleukodystrophy.
3. The risk is 50% for male child in each pregnancy.
PEDIGREE ANSWER 5
1. Autosomal recessive.
2. 25%.
3. Niemann-Pick disease, cystic fibrosis, Tay-Sachs disease, familial
dysautonomia, Canavan disease, glycogen storage disease type 1A,
maple syrup urine disease, Fanconi anemia type C, Bloom
syndrome

OSCE - GENETIC..........................

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