DOWN AND
PATAU
SYNDROME
Fredrik Christopher Gihle
Karlsen
Frederik Glinz
Andrea Femenia Mahiques
INTRODUCTION
DOWN SYNDROME
• Is a genetic disorder caused by the
presence of all or part of a third copy of
chromosome 21.
• It is associated with
• Physical growth delays
• Mild to moderate intelectual disability
(IQ= 50, mental ability of a 8-9 year
old).
• Characteristic facial features: a small
chin, slanted eyes, poor muscle tone, a
flat nasal bridge, a single crease of the
palm, and a protruding tongue…
• They also have an increased risk of a
number of other health problems, including
congenital heart defect, epilepsy, leukemia,
thyroid diseases, and mental disorders.
PATAU SYNDROME
• Is a syndrome caused by a chromosomal
abnormality, in which some or all of the
cells of the body contain extra genetic
material from chromosome 13.
• This disrupts the normal development
leading to organ defects.
• Approximately 90% of infants with Patau
syndrome die within the first year of life.
Those who survive, are typically severely
disabled with:
• Intelectual disability, seizures,
psychomotor issues, physical
characteristic features (ex.
microcephaly, polydactyly, low-set ears,
cleft palate…) abnormal urogenital
system, heart defects …
DOWN SYNDROME
PATAU SYNDROME
Causes of Down syndrome
■ The vast majority of cases (95%) are caused by
trisomy 21, and the incidence increases with maternal
age
■ Maternal meiotic nondisjunction is the usual cause
■ Translocation leads to a familial form of Down
syndrome, with significant risk of the syndrome in
subsequent children
■ From 3% to 5% of cases result from translocation
between chromosome 21 and another chromosome.
The fertilized ovum has three chromosomes bearing
the chromosome 21 material, the functional
equivalent of trisomy 21
Characteristics of Down
syndrome
■ Mental retardation is always present but is highly
variable in degree
■ Large forehead, broad nasal bridge, wide-spaced
eyes, epicanthal fold, large protruding tongue, and
small low-set ears
■ Brushfield spots, small white spots on the periphery
of the iris
■ Short, broad hands with curvature of the fifth finger;
simian crease, a single palmar crease; and an
unusually wide space between the first and second
toes
Complications of Down
syndrome
■ Congenital heart disease, especially defects
of the endocardial cushion, including
atrioventricular valve malformations and
atrial and ventricular septal defects
■ Acute leukemia (20-fold increase), most often
lymphoblastic
■ Increased susceptibility to infection
■ In patients surviving into middle age,
morphologic changes in the brain similar to
those of Alzheimer disease
Maternal screening for Down
syndrome
■ Alpha-Fetoprotein – low
■ Human chorionic gonadotropin (hCG) – high
■ Unconjugated estriol – low
■ The foregoing assays are referred to as the
„triple screen“. When assay for elevated
serum inhibin A is also performed, it is
referred to as the „quadruple screen“.
Expansion of this panel to include other
substances such as pregnancy associated
plasma protein-A (reduced in DS) and
ultrasound studies for physical defects such
as increased nuchal fold has shown promise.
PATAU SYNDROME
Causes of Patau syndrome
■ Autosomal trisomy of chromosome 13
■ Cytogenic types: Meiotic nondisjunction in one parent,
Trisomy 13 mosaicism due to mitotic nondisjunction,
translocation of chromosome 13.
■ Risk Factors: Advanced maternal age, Family history.
Signs and symptoms
■ Microcephaly, neural tube defects, deafness
■ Microphthalmia, cyclopia.
■ Formation of single forebrain with one ventricle (
Holoprosencephaly).
■ Cleft palat/lip, omphalocele, cutis aplasia.
Diagnose and treatment
■ Prenatal ultrasound ( week 11-14)
■ Prenatal diagnosis ( amniocentesis/chorionic villus sampling,
beta-hCG, uE3,AFP, quadruple screen)
■ Postnatal diagnosis: Fluourscence (FISH) karyotyping
■ Treatment: Surgical repair of cardiac defect, cleft palate/lip.
Pallative, supportive.