Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Survey of Human Genetic Disorders First Half > Chromosomal Disorders > Flashcards

Chromosomal Disorders Flashcards

1
Q

What are the major anomalies in the newborn stage of Trisomy 21?

A
  • Heart defect
  • Duodenal atresia
  • Hirschsprung Disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What labs are abnormal in the newborn stage of Trisomy 21?

A
  • Transient myelopoiesis
  • (20-30% risk leukemia)
  • Hypothyroidism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the heart anomalies in Trisomy 21?

A

Heart (50%)
* AV Canal (AVSD) (40%)
* VSD (32%)
* ASD (10%)
* Tetralogy of Fallot (6%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

25-40% of children with duodenal atresia have what disorder?

A

Trisomy 21

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

12% of patients with Hirschprung have what disorder?

A

Trisomy 21

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the physical findings in Trisomy 21?

A
  • Low tone
  • Microcephaly
  • Brachycephaly
  • Upslanting palpebral fissures
  • Epicanthal folds
  • Flat nasal bridge
  • Tongue thrusting
  • Small cupped ears
  • Redundant nuchal (neck) skin
  • Single palmar crease & clindoactyly
  • Sandal gap or proximally placed toes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are complications of Trisomy 21 over time?

A
  • Frequent ear infections with conductive hearing loss (82%)
  • Risk of autoimmune disorders–Thyroid
  • Celiac disease
  • Respiratory infections & immunodeficiency
  • Leukemia 2-3% (if no transient disorder)
  • Visual problems (56%)
  • Atlanto-axial instability (base of skull to spine)
  • Developmental delay. Will need all therapies (occupational,
    physical, speech)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are complications of Trisomy 21 in the adult?

A
  • Premature Alzheimer’s in adults (age 40)
  • Males often infertile
  • Females are subfertile (15-30% fertile)
  • Risk of Trisomy 21 in offspring 35-50%.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the incidence of Trisomy 21 in a 35 year-old pregnant person?

A

1 in 350

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the incidence of Trisomy 21 in a 40 year-old pregnant person?

A

1 in 100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What percentage of nondisjunction occurs in meiosis I in Trisomy 21? Meisois II?

A

77% meiosis I, 23% meiosis II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What percentage of Trisomy 21 is due to a Robertsonian translocation?

A

4%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What percentage of Trisomy 21 is mosaic?

A

1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the recurrence rate of T21 with a Robertsonian translocation?

A

Empirically derived
* t(14:21) 10-15% mother, <5% father

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the recurrence risk of 21q21q isochromosome?

A

100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Is T18 due to nondisjunction in Meiosis I or II?

A

majority Meiosis II

17
Q

What percentage of T18 are mosaic?

A

5%

18
Q

What percentage of T18 are due to translocations or partial duplication?

A

~1%

19
Q

What is the prognosis for T18?

A

Poor. 90% will die by age 1, regardless of intervention

20
Q

What are the clinical findings of T18?

A
  • Everything is small
  • 1/3 are premature, 38% die during labor
  • Characteristic craniofacial features
  • Overriding fingers (contractures)
  • Nail hypoplasia
  • Short hallux
  • Rocker bottom feet
  • Short sternum
  • Major internal malformations
  • Heart defect = 90% (VSD, multiple valve
    anomalies)
21
Q

What are the major anomalies in T18?

A
  • Heart defects:
  • Respiratory: Laryngomalacia, trachoebronchomalacia, apnea, pulm. HTN
  • Ophthalmology: 10% with cataract, corneal opacities. Photophobia is common
  • Small, simple ears, small ear canal. Mod-severe sensorineural hearing loss
  • Limb anomalies: 5-10%, radial aplasia, club foot
  • Scoliosis common in older children
  • Horseshoe kidney in 2/3. UTI’s more common
  • Increased risk for neoplasia: Wilms tumor (1% risk), hepatoblastoma. Average age 5,
    from 12 month to 13 years
  • Brain anomalies in 5%
  • Seizures in 25-50%
22
Q

What are the hallmark features of Trisomy 13?

A
  • HOLOPROSENCEPHALY!
  • CUTIS APLASIA
  • Polydactyly
  • Renal anomalies
  • Eye anomalies (anophthalmia,
    microphthalmia)
23
Q

What are the prenatal findings in Turner syndrome?

A

Hydrops, cystic hygroma, heart defect

24
Q

What are the physical features of Turner syndrome?

A
  • Webbed neck
  • Downslanting eyes
  • Low set ears, posteriorly rotated
  • Wide chest (shield chest, wide
    spaced nipples)
  • Puffy hands and feet (edema)
  • Hyperconvex nails
25
Q

What are the older presentations of Turner syndrome?

A

Short stature
* SHOX deficiency
* Madelung deformity (radius shortened)
* Responsive to growth hormone

Streak gonads–> amenorrhea and lack of pubertal development
* Endocrinology referral for sexual development
* Subfertility to infertility is typical
* Premature ovarian failure

Hypothyroidism: Yearly thyroid testing

26
Q

What are features of Klinefelter syndrome?

A

Hypergonadotropic hypogonadism
* Pituitary function normal, nonresponsive
testes
* Male factor infertility

Tall stature (extra SHOX copy)
Low tone
Some difficulties in school related to reading and language
Problems with emotional regulation

27
Q

What is the genetic change in Wolf-Hirschhorn?

A

Del 4p15.3

28
Q

What are findings that are present in over 75% of individuals with Wolf-Hirschhorn?

A
  • IUGR/postnatal growth
    deficiency
  • *Intellectual disability—
    absent speech
  • Hypotonia
  • Muscle hypertrophy
  • *Seizures
  • Feeding difficulties
  • Abnormal ears
29
Q

What are findings that are present in 50-75% of individuals with Wolf-Hirschhorn?

A
  • Distinctive EEG
    abnormalities
  • Skeletal anomalies
  • Craniofacial asymmetry
  • Abnormal teething
  • Ptosis
  • *Antibody deficiency
30
Q

What are findings that are present in 25-50% of individuals with Wolf-Hirschhorn?

A
  • *Heart defects
  • Hearing defects
  • *Eye/optic nerve defects
  • *Cleft/lip palate
  • Stereotypies
  • Structural brain
    anomalies
  • Genitourinary tract
    defects
31
Q

What referrals/evaluations should be placed for an individual with Wolf-Hirschhorn?

A
  • Heart defect (cardiology, echocardiogram)
  • Coloboma, eye anomalies (ophthalmology)
  • Hearing defect (audiology)
  • Cleft lip/palate (plastic surgery/ENT)
  • Seizures (EEG/neurology)
  • Renal anomalies (Urinalysis, renal ultrasound)
  • Scoliosis, club foot (orthopedics)
32
Q

What is the genetic change in Cri Du Chat?

A

5p-

33
Q

What are the main features in Cri Du Chat?

A
  • Laryngeal malformation resulting in
    high pitched monotone cry
  • Developmental delay/intellectual
    disability
  • Craniofacial findings
  • Other congenital anomalies
34
Q

What are the medical problems in 5p- (Cri Du Chat)?

A

Congenital heart disease 35%

Abnormal MRI 30%
* Absence corpus callosum
* Small cerebellum

Renal abnormalities 18%
* Small kidneys, ectopic

Genital abnormalities
* Cryptorchidism
* Inguinal hernia

Developmental delay
* Moderate to severe

35
Q

What percentage of 5p- (Cri Du Chat) are paternal in origin?

A

80-90%

36
Q

What percentage of 5p- (Cri Du Chat) are from unbalanced parental translocations?

A

10% to 15%

37
Q

What is the genetic cause of Cat-Eye syndrome?

A
  • Isodicentric marker 22q11, resulting
    in tetrasomy
  • Note that the marker chromosome
    regions are proximal to the deletion
    22q11.2 critical region
38
Q

What are the features of Cat-Eye syndrome?

A
  • Coloboma – the “cat eye”
  • Preauricular anomalies (pits, tags)
  • Hearing loss
  • Heart defect
  • Renal anomaly
  • Anal atresia
  • Intellectual disability (mild)

Survey of Human Genetic Disorders First Half (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions