Chromosomal disorders

Question 1

Patau’s

Answer 1

Trisomy 13 -1: 140000
80% die in a month

microcephaly
Microphtalmia (small eyes)
cleft lip/palate
polydactylyl
omphalocele/gastrochisis
scalp lesions

VSD, PDA, dextrocardia

bad prognosis

USS in 2nd trimester
amniscietesis

Question 2

Edwards

Answer 2

trisomy 18 - 18wards. 1:14000
most die at birth but CAN live longer

Low birth weight -LBW
small mouth/chin
Low set ears
! rocker bottom feet - thick feet -not flat at bottom but arching out (like a bun)
! Overlapping fingers
intellectual problems

cardiac (VSD), renal and GI issues

Omphalocele/gastrochisis

bad prognosis

USS in 2nd trimester
amniscintesis

Question 3

Noonan’s

Answer 3

Mutated RAS/ MAPK

Webbed neck
trident hairline 
Pectum excavatum
Short stature
Pulmonary stenosis

Question 4

Turners

Answer 4

45 XO 1:2500
90% -misscarriage

Neonate -
Pyloric stenosis
! cardiac problems (coarcation of aorta, bicuspid valve)
Bicuspid aortic valve > Aortic coarctation
AS -ESM 
Lymphoedema in hands and feet
spoon shaped nails
Omphalocele/gastrochisits
! cystic hygromas
Renal issues

later-
short stature
infertility
delayed puberty
Hypothyroidism

Question 5

Management of Turners

Answer 5

Growth hormone replacements

Ovarian hormones replacements

Question 6

Kleinfelters

Answer 6

45 XXY - 1:1000 births

Infertility
Small gonards
tall stature
Gynecomastia
IQ normal and look normal

Question 7

Fragile X

Answer 7

1 in 4,000, CGG trinucleotide repeat expansion mutation
the more repeats the worse -over 200 to get fragile X
(like huntington and myotonic dystrophy)
X-linked, some males can be only carriers (incomplete penetrance) CGG trinucleotide repeat expansion mutation

macrocephaly, macrogonadism
Large, Low set ears
Long thin face
autism, join mobility, scoliosis
Low IQ (20-80)- 2nd most common cause after downs

Question 8

Prader Willis and Angelman

Answer 8

Imprinting disorder - lack of paternal (PRADER-FATHER) of Chr 15 -PWS
Lack of MATERNAL -Angelman
different disorders
either de Novo or parental disomy

PWS -
Hypotonia 
Hyperphagia 
almond shaped eyes
hypogonadism
Epicanthal folds (asian eyes)
Flat nasal bridge + upturned nose 
Learning disability
! obesity

Angelman-
wide smile face constant
learning disability

Question 9

Management of PWS

Answer 9

Growth hormone if failure

feeding and nutritional councelling if obese

Question 10

What is down’s. pathogenesis and risk factors

Answer 10

trisomy 21 - age of parents (esp mum is risk)
94% causes by non dysjunction
5% transolcation
1% mosaicism (milder

Question 11

Signs and Sx of Down’s

Answer 11

Cranium -
round face, flat nasal bridge, epicanthic folds (asian eyes)
Small mouth/eyes, short neck, 3rd fontanelle
! Brushfield spots in iris -white discolored spots

Single palmar crease
Sandal gap
hypotonia

Birth issues -
Cardiac -40% AVSD
Duodenal atresia
Hirsprung disease
Omophacele +/- umbilical hernia

later -
Learning disability 
delayed motor milestones
Short stature
 ! OTITIS media
visual impairments
! Obstructive Sleep Apnea (75%)

Assocaited diseases:
Kostman’s. Blooms
Fanconi, LF1

Leukemias (not ALL)
! Hypothyroidism, coeliac
Epilepsy and alzheimers

Question 12

Management of Down’s syndrome

Answer 12

Neonate/immediate care –
Evaluate for AVSD (echo) and Duodenal atresia
If signs of development delay - OT/SALT/Physio as soon as possible

Later -
annual ear, eye and thyroid checks
appropriate education and plan
heamoglobin (IDA)
Monitor of obtrustive sleep apnea
monitor growht charts

support with local Downs group
local parents support groups