Chromosome Abnormalities (Bbd Iii)

Front 1

What is the most common type of chromosome anomaly?

Back 1

Sporadic trisomies

Front 2

What is the most common trisomy?

Back 2

Trisomy 16
It is incompatible with life

Front 3

What is the most common chromosomal anomaly compatible with life?

Back 3

Trisomy 21

Front 4

What are the general characteristics of children with Trisomy 21?

Back 4

1. Multi-system anomalies
2. Congenital heart defects
3. Hypotonia (floppy)
4. Developmental Impairment
5. Increased risk of leukemia
6. Nuchal thickening
7. Small, C-shaped ears

Front 5

What is the maternal age effect?

Back 5

As mothers age, so do their eggs. This leads to a greater possibility of nondisjunction and thus a child with Trisomy 21.

Front 6

What are the general characteristics of children with Trisomy 18?

Back 6

1. Small for gestational age
2. Severe CNS malformations
3. Multi-system anomalies
4. Neurologic Fisting
5. Rocker bottom foot
6 Syndactyly of toes 2 and 3
7. Scissoring of legs
8. Hypogonadism
9. Overwhelming majority die withing first 6 to 12 months

Front 7

What are the general characteristics of children with Trisomy 13?

Back 7

1. Craniofacial anomalies (punched out areas on scalp)
2. Severe brain defects
3. Heart defects
4. Most die withing first few months of life if they weren't spontaneously aborted already

Front 8

What are the general characteristics of children with 4-P Syndrome: Wolf-Hirschhorn Syndrome?

Back 8

1. Trojan like face
2. Multiple congenital malformations
3. Mod. to severe developmental impairments (microencephaly)
4. Seizures
5. Ambiguous genitalia
6. Coloboma (pupil goes into iris)

Front 9

What are the general characteristics of children with cri-du-chat (5p-)?

Back 9

1. Deletion of short arm of chromosome 5
2. Severe developmental retardation (microcephaly)
3. High pitched, "cat-like" cry
4. Simplistic face
5. Aggressive behavioral pattern
6. No interest in self-help activities (potty training etc.)

Front 10

What are the general characteristics of children with Turner Syndrome (Monosomy X)?

Back 10

1. Puffy hands and feet at birth
2. Small stature
3. Nuchal webbing
4. Congenital heart defects
5. Absent or delayed sexual maturity

Front 11

What is mosaicism in regard to monosomy x?

Back 11

1. Not all of your cells are monosomy X (20% of those with Turners)
2. If you have mosaicism there is a possibility of still becoming pregnant

Front 12

What are the general characteristics of children with Klinefelter Syndrome (47, XXY)?

Back 12

1. Small, firm to hard testes
2. Tall stature
3. Increased probability of learning difficulties
4. Infertile
5. Breast enlargement and female fat distribution
6. Low testosterone: elevated LH/FSH
7. 1 in 700-1000 males

Front 13

What does it mean to have contiguous gene syndromes (segmental aneusomy)?

Back 13

Disorders that result from the deletion or duplication of adjacent genes in a specific chromosomal region

Front 14

What is a well-known contiguous gene syndrome?

Back 14

DiGeorge syndrome

Front 15

What are the general characteristics of children with a deletion of 22q11.2 (DiGeorge and other contiguous gene syndromes)?

Back 15

1. Craniofacial anomalies
2. Feeding/failure to thrive
3. Hearing loss
4. Cognitive/developmental delay
5. Mental illness
6. Autism spectrum disorders
7. Cardiac defect
8. Small/absent thymus
9. Endocrine abnormalities

Front 16

What are the general characteristics of children with Williams syndrome?

Back 16

1. Characteristic facies(make sure you pick up the right child at the picnic)
2. Cardiovascular anomalies
3. Infantile hypercalcemia and growth retardation
4. 1 in 10,000 births

Front 17

What are the indications for performing a chromosome analysis?
Possible Test Question

Back 17

1. Neonate with multiple congenital anomalies
2. Mental retardation and developmental delay with or without congenital anomalies
3. Down syndrome
4. Family Hx of Down syndrome
5. Recurrent spontaneous abortions
6. Abortus tissue
7. Couple with Hx of infertility
8. Short stature in female with primary amenorrhea
9. Ambiguous genitalia

Front 18

What is the one diagnostic test you always perform if you suspect any chromosome anomaly?

Back 18

Echocardiogram

Front 19

Who is mitochondrial DNA inherited from?

Back 19

Mother, but "male leakage" is documented

Front 20

True or False
Mitochondrial DNA sequences are more susceptible to mutation than nuclear DNA.

Back 20

True

Front 21

What is the pattern of mitochondrial inheritance with regard to a pedigree?

Back 21

Affected female has all affected children
(inheritance may resemble Mendelian autosomal dominant)

Front 22

What is the frequency of of mitochondrial disorders?

Back 22

1 in 5,000

Front 23

What do mitochondrial disorders primarily affect?

Back 23

Nerve and muscle tissue which rely heavily on high levels of energy production

Front 24

Human triploid fetus characteristics (paternal inheritance vs. maternal inheritance)

Back 24

1. 2 paternal and 1 maternal set of chromosomes have large, cystic placentas and poorly developed fetus.
2. 2 maternal and 1 paternal genome yields a very small placenta but relatively well developed fetus.

Front 25

Characteristics of Prader-Willi Syndrome

Back 25

1. Chromosome 15 q11-13
2. Absent paternal gene expression
3.Hypothalmic insufficiency
4. Hypotonia
5. Developmental delay
6 Hyperphagia leading to obesity
7. Mental impairment

Front 26

Characteristics of Angelman Syndrome

Back 26

1. Chromosome 15q11-13
2. Absent maternal gene expression
3.Severe developmental delay and mental impairment
4. Inappropriate happy demeanor including frequent laughing, smiling, and excitability
5. Gait ataxia (puppet-like)
6. Seizures

Front 27

Characteristics of Sotos Syndrome

Back 27

1. Related to defect in tumor suppressor genes
2. Big brain; dilated ventricules; extra axial fluid
3. Angular facies
4. Risk of embrynal tumors
5. Assymetric
6. Interesting Gait

Front 28

Characteristics of Beckwith-Weidemann syndrome

Back 28

1. Associated with tumor suppressor genes
2. Macroglossia
3. Everything is just bigger
4. High risk of embrynal tumors
5. Cognitively normal
6. Hypoplasia of islet cells and leads to hypoglycemia

Front 29

General Facts about Trinucleotide repeats

Back 29

1. Usually results in down regulation of transcription of associated gene
2. Associated with neurological degeneration
3. Autosomal dominant or X-linked recessive predisposition
4. Common Conditions: Huntington Chorea
Fragile X
Myotonic dystrophy
Spinocerebellar ataxias

Front 30

Characteristics of Fragile X

Back 30

1. X-linked dominant
CGG repeats (>200 has full mutation)
2. Mod-severe in boys; milder in girls
3. Delayed motor and verbal development
4. Autistic features
5. Hypermobility

Front 31

Indications for testing for Fragile X Syndrome

Back 31

1. Male family member who is autistic
2. Male(s) with learning disability
3. Female with learning disability planning to have a child
4. Family member with a serious learning problem and/or mental retardation
5. Family member with developmental delays especially in speech and gross motor skills

Front 32

Characteristics of Incontinentia Pigmentia

Back 32

1. Clinical expression related to pattern of X-chromosome inactivation
2. X-linked dominant disorder with lethality in males
3. Germ line mosaicism

Front 33

Characteristics of Cat-eye syndrome

Back 33

1. Mosaicism for a marker chromosome derived from chromosome 22
2. Partial trisomy 22

Front 34

Killian-Pallister Syndrome

Back 34

1. Tetrasomy 12p mosaicism
2. Usually identified only in skin fibroblast cultures
3. Blood chromosome analysis is usually normal