paediatric genetics

Question 1

down syndrome

Answer 1

trisomy 21

learning disability
congenital heart disease
hypothyroidism 
immunity 
early onset alzeihmer disease

Question 2

congenital

Answer 2

present at birth

genetic or environmental or both

Question 3

multiple congenital anomaly syndromes

Answer 3

individually rare
common as a group

syndrome = pattern of clinical features occurring together

Question 4

description of the dysmorphic child

Answer 4

position and shape of facial features
hands
growth of child
general features

Question 5

describing head

Answer 5

shape
size: macrocephaly, microcephaly
ear position: low set, posteriorly rotated indicated lack of maturity

Question 6

describing eyes

Answer 6

hypertelorism (eyes too far apart)- innercanthal distance and inter-pupillary distance increased

telecanthus/epicanthic folds
-ICD and IPD increased

Question 7

hand measurements

Answer 7

finger length
digital abnormalities
palmar creases

Question 8

finger descriptions

Answer 8

arachnodactyly

brachydactyly - short fat fingers

Question 9

malformation

Answer 9

can occur by itself or part of a syndrome

Question 10

polysyndactyly

Answer 10

malformation

too many fingers and some are stuck together

Question 11

acrocephalopolysyndactyly

Answer 11

Greig’s syndrome

tall forehead
polydactyly
syndactyly

Question 12

sequence

Answer 12

one abnormality leads to another, can have multiple causes

Question 13

pierre-robin sequence

Answer 13

small chin which progresses to cleft palate

Question 14

deformation and disruption

Answer 14

pattern of development normal to start with but becomes abnormal

deformation: organ parts are there
disruption: parts of organ/body part absent
e. g. amniotic bands

Question 15

association

Answer 15

2 or more features occur together more often than expected by chance

Question 16

association example: VATER syndrome

Answer 16

vertebral anomalies
ano-rectal atresia
tracheo-oesophageal sphincter
radial anomalies

Question 17

syndrome

Answer 17

a distinct group of symptoms and signs which, associated together, form a characteristic clinical picture or entity

Question 18

turner syndrome

45, X

Answer 18

lymphoedema 
increased carrying angle
low hairline 
sandal gap 
short stature
coarctation of aorta
hypothryiodism 
htn 
primary amenorrhoea + infertility

Question 19

genetic investigation of learning disability

Answer 19

microarray - chromosome number
fragile X gene
targetted test driven by phenotype

trio based exome or trio based genome analysis

Question 20

22q11 deletion
(DiGeorge)

Answer 20

cardiac defects
abnormal facies
thymic hypoplasia
cleft palate
hypocalcaemia

Question 21

importance of phenotyping

Answer 21

key to assessment of clinical relevance is phenotype

why accurate description of clinical features is important