Case 29: Hypotonia, Infant

Front 1

List common features of down syndrome?

Back 1

• upslanting palpebral fissures
  
• small ears
  
• flattened midface
  
• epicanthal folds
  
• redundant skin on back of neck (nuchal skin)
  
• hypotonia (most consistent finding in infants
  

Front 2

Karyotypes causing down syndrome?

Back 2

• tirsomy 21
  
• unbalanced translocation resulting in extra chromosome 21 materal
  
• mosaicism for a trisomy 21
  

Front 3

Link between down syndrome and hypothyroidism?

Back 3

increased chance

Front 4

List some indications for chromosomal analysis in pediatric patients

Back 4

• clinical features of known chrom disorder
  
• unrecognizable malformation syndrome
  
• mental retardation and other unusual findings (including short stature)
  
• stillborn with multiple malformations
  
• chromosome breakage syndrome
  
• tumour
  

Front 5

When to do FISH?

Back 5

submicroscopic deletions

Front 6

How to exclude mosaicism

Back 6

virtually impossible

but, results can imply baby is probably not mosaic

use cytogenetics

Front 7

Risk factors for down syndrome

Back 7

can be born to any couple, regardless of age

chance, though, increases as mother's age increases

Front 8

How common is Down Syndrome in US?

Back 8

1/700 births

Front 9

Risk of CVS?

Back 9

Direct diagnostic test

slight risk of causing miscarrage

Amnio, as well, has this risk

Front 10

How to screen for Down Syndrome?

Back 10

measure of maternal serum

detailed ultrasonography, nuchal skin thickness, nasal bone ossification, other growth parameters

Front 11

What is fragile X syndrome?

Back 11

X-linked disease

caused by inheritance of abnormal number of CGG repeats in FMR1 gene

Front 12

Physical features of fragile X syndrome?

Back 12

• long face with large mandible
  
• large, prominent ears
  
• large testicles, after puberty
  

Front 13

What is the most common genetic cause of intellectual disability?

Back 13

With the exception of Down syndrome, Fragile X syndrome is the most common genetic cause ofintellectual disability.

Front 14

List two disorders of sex chromosomes

Back 14

Turner Syndrome

Klinefelter syndrome

Front 15

Physical findings of turner syndrome?

Back 15

• webbed neck
  
• low ear placement
  
• edema of hands/feet
  
• hyperconvex nails
  
• shield chest, wideley spaced nipples
  
• coarc of aorta
  
• short stature
  
• normal IQ
  

Front 16

Is turner syndrome common?

Back 16

1/2000 females

Front 17

Findings of klinefelter syndrome?

Back 17

normal appearing at birth

may not be diagnosed until adulthood

infertility due to testicular atrophy

eunochoid body habitus

gynecomastia

IQ varies

Front 18

Differences between 47 XXX or 47 XYY?

Back 18

• Developmental delay and decreased IQ is more common in 47, XXX.
  
• Adults with 47, XYY may be taller than average.
  
• IQ tends to be in the low-normal range.
• There may be an increased incidence of behavior problems.

Front 19

List some common trisomies

Back 19

• Trisomy 13 (Patau syndrome)
  
• Trisomy 18 (Edwards syndrome)
  
• Trisomy 21 (Down syndrome)
  

Front 20

Trisomy 13

Back 20

• polydactyly
  
• cleft lip and palate
  
• cardiac and renal defects
  
• umbilical hernias
  
• cutis aplasia
  

Front 21

Trisomy 18

Back 21

• severe intellectual disability
  
• prominent occiput
  
• micrognathia
  
• low set ears
  
• short neck
  
• overlapping fingers
  
• heart defects
  
• renal malformations
  
• limited hip aduction, rocker bottom feet
  

Front 22

Trisomy 21

Back 22

• Intellectual disability
  
• epicanthic folds; flat facial profile
  
• single palmar crease, redundant neck skin
  
• heart defects
  
• intestinal stenosis
  
• umbilical hernia
  
• predisposition to leukemia
  
• hypotonia
  
• gap between first and second toes
  

Front 23

Is short stature common in down syndrome?

Back 23

• yes
  
• seen after infancy
  
• hypothyroidism, though, can also lead to short stature, so important to know child's thyroid status
  

Front 24

How to encourage parental advocacy?

Back 24

• IEP

Front 25

How to share difficult news?

Back 25

SPIKES!

families need time to process a diagnosis and its medical implications

Front 26

DDx of hypotonia in a newborn?

Back 26

• down syndrome
  
• benign neonatal hypotonia
  
• zellweger syndrome
  
• family resemblance
  

Front 27

Down syndrome

Back 27

Remember that almost all of the findings in can be seen individually in people who do not haveDown syndrome. It is the combination of findings that separates a syndrome from normalvariation

Front 28

Benign neonatal hypotonia

Back 28

Generally not associated with unusual facial or hand features

Front 29

Zellweger syndrome

Back 29

Infants with Zellweger syndrome-a peroxisomal disorder-are generally hypotonic and poorlyresponsive.

Front 30

Family resemblance

Back 30

While family resemblance may account for one or two clinical findings in a child, it is usually notseveral findings associated with a syndrome.

Front 31

Diagnostic tests for trisomy 21?

Back 31

• lymphocyte karyotype
  
• FISH
  
• cytogenic studies on skin fibroblasts
  
• ECG used to confirm cardiac malformations
  

Front 32

Follow up evaluation for children with down syndrome?

Back 32

• annual thyroid screen
  
• vision screen
  
• hearing screen
  
• CBC in first month
  
• referral to pediatric cardiologist
  
• starting at 1 year, hemoglobin and hematocrit to assess for iron deficiency anemia
  
• spine instability follow up