Genetic Disorders and Disorders of Sexual Development Flashcards
What is the karyotype of Down syndrome?
(trisomy 21)
47 XX or XY, +21
What is robertsonian translocation?
chromosomal abnormality where the entire long arms of two different chromosomes become fused to each other.
Mosaicism
defined as the presence of ≥ 2 population of cells within an individual
Clinical findings of one with Down’s Syndrome.
intellectual disability,
mongoloid facial features (flat face, low-bridged nose, and epicanthal folds)
Brushfield spots (speckled appearance of the iris)
muscular hypotonia,
broad short neck,
palmar (simian) crease
congenital heart defects (endocardial cushion defect)
duodenal atresia (‘double-bubble sign”
Hirschsrpung disease
15 -20 increase chances of:
ALL
Alzheimers disease
What are test done to see if someone has Downs syndrome?
maternal serum tests,
US
amniocentesis
chorionic villus sampling
What is the karyotype of Edwards Syndrome?
trisomy 18 caused by nondisjunction
Clinical findings Edwards Syndrome.
intellectual disability
low set ears and micrognathia
congenital heart defects
overlapping flexed fingers
rocker-bottom feet
What is the karyotype for Patau Syndrome?
trisomy 13 caused by nondisjunction
Some clinical features of Patau Syndrome?
intellectual disability,
cleft lip and/or palate,
cardiac defects,
renal abnormalaities,
microcephaly,
holoprosencephaly,
polydactyly
What is the pathogenesis behind Cri du chat?
due to deletion of the short arm of chromosome 5
Clinical findings Cri du chat syndrome?
high-pitched catlike cry,
intellectual disability,
congenital heart disease
microcephaly
Where is the retinoblastoma gene?
13q14 gene long arm chromosome 13 deletion
What are clinical findings in WAGR?
WAGR complex consists of:
Wilms tumor, aniridia, genitourinary anomalies, and intellectual disability (formerly known as mental retardation)
What gene affected in WAGR?
11p13 (short arm chromosome 11 deletion)
Name some disorders characterized by chromosomal deletions?
Cri du chat
retinoblastoma
WAGR
What is Klinefelter syndrome caused by? It is a common cause of what presentation in males?
by meitoic nondisjunction and is common cause of male hypogonadism
Most common karyotype for Klinefelter?
47, XXY
Describe the hormone levels in Klinefelter?
FSH and LH are elevated while testosterone is high
What are the clinical findings for Klinefelter?
- testicular atrophy,
- infertility due to azoospermia,
- eunuchoid body habitus,
- high-pitched voice
- gynecomastia
- female distribution
What is the most common karyotype of Turner syndrome?
45, X