Genetic and Congenital Defects Flashcards
Chromosomal abnormalities and inborn errors in metabolism
What is Trisomy 21?
Down Syndrome
What is a simian crease? What is it associated with?
Longitudinal crease on hands associated with down syndrome
What is an epicanthic fold? What is it associated with?
Inner eyelid fused to nose bridge associated with down syndrome
Protruding tongue, simian crease, and epicanthic fold are all physical characteristics of…
Down Syndrome
What is tetrology of Fallot? What is it associated with?
Congenital heart anomaly associated with down syndrome
What is trisomy 18?
Edwards Syndrome
What are the physical characteristics of Edwards Syndrome?
- Severe cardiac malformations
- “Rocker-bottom” feet
- Clenched hands
- Low-set ears
What is the prognosis or life expectancy for Edwards Syndrome?
Majority die in utero or within 1 year
What is trisomy 13?
Patau Syndrome
Which defect is characterized by a cleft lip and palate, sometimes into the nasal cavity?
Patau Syndrome
Besides a cleft lip or palate, how does Patau Syndrome affect the body?
- Severe cognitive and growth delay
- Nervous system and cardiac malformations
What is the prognosis of Patau Syndrome?
Not compatible with long life
Describe the chromosomal defect in Cri-du-chat syndrome
5p- syndrome: deletion of portion of the p-arm on chromosome 5
Infants with cri-du-chat syndrome are best known for their…
high-pitched cry that sounds like a cat
Which disorder causes widely set eyes (hypertelorism), low-set ears, a small jaw, and a rounded face?
Cri-du-chat syndrome
An infant has intellectual disability, delayed development, microcephaly, low birth weight, and weak muscle tone (hypotonia).
What is the likely congenital defect?
Cri-du-chat syndrome
How might cri-du-chat syndrome affect organs?
Several organ defects possible
What are the chromosomes of someone with Kleinfelter Syndrome?
47, XXY (biologically male)
What are the symptoms of Kleinfelter Syndrome?
- Male hypogonadism and infertility (due to lack of androgens)
- Tall, thin, relatively long legs
- High-pitched voice
- Gynecomastia (breast development)
What are the chromosomes of someone with Turner Syndrome?
45, X or X, O (biologically female)
What are the physical characteristics of Turner Syndrome?
Short stature with webbed neck (due to extra soft tissue)
What are the effects of Turner Syndrome on the reproductive system?
Females will have primary amenorrhea (no menses, no ovulation) and sterility
Lesch-Nyhan syndrome is an X-linked deficiency of the enzyme…
hypoxanthine-guanine phosphoribosyltransferase (HGPRT)
Lesch-Nyhan syndrome causes accumulation of…
uric acid in body fluids
(associated with gout and kidney dysfunction as well as brain damage)
What are neurological signs of Lesch-Nyhan syndrome?
Poor muscle control and cognitive disability in first year of life
What is characteristic of the second year of life with Lesch-Nyhan syndrome?
Self-mutilating behaviors, ie lip and finger biting
Lesch-Nyhan syndrome damages what part of the brain? What does this cause?
Basal ganglia damage leads to writhing movements
With Lesch-Nyhan syndrome, poor utilization of vitamin B12 may lead to…
megaloblastic anemia
Phenylketonuria (PKU) is an autosomal recessive deficiency of the hepatic enzyme…
phenylalanine hydroxylase
PKU means high levels of phenylalanine which leads to…
progressive mental deterioration in the first few years of life
If an affected infant appears normal at birth, but cognitive disability is evident within a few months, what defect is most likely?
Phenylketonuria (PKU)
The inability to convert phenylalanine to tyrosine leads to…
So, infants with PKU tend to…
leads to reduced melanin synthesis
so, infants with PKU tend to have fair skin, blonde hair, and blue eyes
Which defect can be characterized by a mousy or musty odor? Why?
PKU, due to production of phenylacetic acid
What is one treatment for PKU?
Phenylalanine-restricted diet
Alkaptonuria/Ochronosis is a defect in the enzyme… which participates in…
the enzyme homogentisate 1,2-dioxygenase (HGD), which participates in tyrosine degredation
If urine demonstrates oxygenation of homogentisic acid, which defect is most likely?
Alkaptonuria/Ochronosis
What are some symptoms of Alkaptonuria/Ochronosis?
- Degenerative arthropathy (bilateral painful joints)
- Cola colored urine (rapid oxidation)
- Spots on skin
