Lecture 10/3- Genetics Flashcards
what is FISH? what does it show?
Fluorescent in situ hybridization
Use DNA probes to look at karyotype in more detail
what is direct DNA analysis?
PCR for a particular gene (ie BRCA)
what uses tiny DNA probes?
Microarray Comparative Genomic Hybridization
what are the most common cause of congenital malformation syndromes?
Unknown causes
List some autosomal dominant disorders?
Marfan’s Syndrome
Huntington’s Chorea
Achondroplasia
Neurofibromatosis
Autosomal dominant disorder are often related to genes that code for what?
structural proteins (collagen)
most common autosomal recessive disorders you will pick up in peds?
inborn errors of metabolism
List some autosomal recessive disorders
PKU – phenylketonuria Galactosemia Homocystinuria Cystic fibrosis CAH congenital adrenal hyperplasia Sickle cell anemia
Autosomal recessive disorders involve mutations in genes that usually code for what?
enzymes.
are also associated with serious illness and shortened life span
what is hemophilia’s problem?
bleeding in the joints
what are some sex linked disorders?
Fragile X syndrome
Duchenne and Becker muscular dystrophy
G6PD deficiency
Hemophilia A
what is an X linked dominant disorder
Rett Syndrome (girls)
normal karyotype, 2 copies of 1 chromosomes from 1 parent
Uniparental Disomy
the presence of an extra chromosome
Trisomy
the absence of a whole chromosome
monosomy
the 180° rotation of a part of a chromosome
Inversion
the breakage and rejoining of parts of two, non-homologous chromosomes
Translocation
Uniparental disomy is thought to be ….
from a “rescue mechanism” for a trisomy (or monosomy)
Example 15q11.2 chromosome
If you have 2 copies of 15q11.2 from mom what syndrome do you have?
Prader Willi Syndrome
If you have 2 copies of 15q11.2 from dad what will you have?
angelman syndrome
What is T13?
Patau syndrome
what type tone do kids with Down Syndrome have?
Decreased tone
what will the eyes of a child with down syndrome look like?
mongoloid slant to eyes with epicanthal folds
eyes slant up just a bit (laterally)
what will the face of a child with down syndrome look like?
small midface
depressed nasal bridge
how do you plot the growth of a child with down syndrome?
plot on a growth chart
what is a common heart problem in children with down syndrome?
AV canal due do endocardial cushion defect
VSD< ASD, valve disorders
what endocrine disorder are down syndrome kids at risk for?
hypothyroidism
what GI problems will children with down syndrome have?
duodenal atresia
tracheo-esophageal fistula
people with down syndrome have a greater risk of developing what cancer?
leukemia
what trisomy is likely to die before delivery?
Trisomy 13- Patau’s
what occurs with children with T18- Edwards syndrome?
Cleft lip/ palate
congenital heart disease
horseshoe kidneys (fused in middle)
pyloric stenosis
Where do Patau’s syndrome (T13) occur?
Midline problems
like Edward’s with holoprosencepahly 9failure of brain to divide)
Abnormal hands/feet- rocker bottom better, clinodactyly
what occurs with DiGeorge syndrome? (deletion on 22q11)
Tetraology of Fallot hypoplastic thymus (see on x-ray) immunodeficiency absent parathyroid hypocalcemia nose full in lower part of bridge mouth is small and slack low ears
Main symptoms with Cri du chat (5 p deletion)?
laryngeal hypoplasia, high pitched cry
If you see rocker-bottom feet what should you suspect?
Trisomy 13 (potentially 18)
other problems with 5 p deletion.
Developmental delay
craniofacial dysmorphism
clef lip/ palate
what is the most common cause of cognitive disabilities in males?
Fragile X
what is associated w/ Fragile X?
social anxiety
learning disabilities
ritualistic behaviors
Other physical manifestations of Fragile X?
hyperextensiability of joints
pectus excavatum
large testicles
Main features of Kinefelter Syndrome
Hypogonadism and lack of sexual development
Gynecomastia
Infertility
How do you treat a male with Klinefelter Syndrome?
hormone replacement
what is the standard width between eyes?
One extra eye
features of achondroplasia
large head and forehead
long bones are short
how would you describe the forehead of a person with achondroplasia
frontal bossing
Clinically significant abnormalities in either form or function. Result from error in morphogenesis ( 1st trimester)
Congenital malformation
Normal morphogenesis but environmental factors disturb normally developing tissue
Deformation
A single malformation leads to other structural changes
Malformation Sequence
Recognizable pattern of anomalies that results from a single identifiable underlying cause – may include malformations, deformations
Malformation Syndrome
what is an example of a malformation syndrome?
T21- cardiac, craniofacies, CNS, limbs
whats an example of a malformation sequence?
Pierre Robin
primary- failure of growth of mandible which secondarily leads to U shaped cleft palate and glossoptosis
problems with Pierre Robin sequence?
difficultly eating
on back, tongue may block trachea
What are Recognizable pattern of malformations?
Association
What does VACTERL stand for?
Vertebral anomalies Anal atresia Cardiac defects Tracheoesophageal fistula Renal anomalies Limb anomalies
What does CHARGE stand for?
C- Coloboma of the eye, central nervous system anomalies
H - Heart defects
A - Atresia of the choanae
R - Retardation of growth and/or development
G - Genital and/or urinary defects (Hypogonadism)
E - Ear anomalies and/or deafness
which time is a fetus most susceptible to teratogens?
1st trimester
what are some potent vasoconstrictions
tobacco
cocaine
meth
what days are there a high degress of sensitivity
days 18-60
when does a cleft palate occur?
during the embryonic and early fetal stages
what can the cleft palate affect?
pituitary gland
what are some bacterial diseases that are teratogens
Syphilis
Gonorrhea (NB)
Chlamydia (NB)
what will a child with fetal alcohol syndrome have?
Smooth philtrum
short palpebral fissures
flat midface
thin upper lip
are anticonvulsants a teratogen?
Yes
TORCH presentation
Thrombocytopenia – petechiae Hepatolsplenomegaly IUGR Microcephaly Hydrocephalus Mental Retardation
Inborn errors of metabolism are typically missing what?
an enzyme which lead to an excess of substrate or deficiency of product
2 examples of carbohydrate disorders
Glycogen storage diseases
galactosemia
what happens with glycogen storage disease
glycogen can’t be convert glucose.
Fats for energy leads to ketones
Protein for energy leads to ammonia
how can you treat glycogen storage disease?
Limit free sugar, infusionsof uncooked cornstarch for slow release of glucose
What happens with galactosemia?
accumulation of galactose -1- phosphate in liver and renal tubules
List some amino acid disorders
Urea cycle disorders
Tyrosinemia
Homocystinuria
PKU
what causes PKU
lacking enzyme that turns phenyalanine into tyrosine
in PKU what does phenylalaine turn into and is found in the urine?
phenylpyruvic acid
General characteristics of IEM?
Failure to thrive lethargic vomiting (severe) progressive ataxia acidosis
what organ doesn’t function well if you are very acidodic?
Heart
what can a baby with IEM present like?
Shock
flu-like
how can you look for acidosis?
Blood gas
if its a carb disorder what might you have?
low blood glucose
if your ammonia levels are high what are you using for energy?
proteins
If a baby shows up in shock what three things should you suspect
Infection
Inborn error of metabolism
cardiac problem
If you were using fatty acids for energy what lab would you want to see?
Lactate
