Neuro Peds - 03 - Other Genetic Disorders

Question 1

What is the leading cause of inherited mental retardation?

Answer 1

Fragile X syndrome is the leading inherited cause of mental retardation (p. 210).

Question 2

When one parent is a carrier for CF, what chance does each child have of being affected?

Answer 2

When one parent is a carrier for CF, the child has a 50% chance of being a carrier

Question 3

What genetic disorder produces muscle weakness without cognitive impairment?

Answer 3

Spinal Muscular Atrophy (SMA)

normal intelligence

Question 4

What are the three mechanisms by which chromosome abnormalities occur?

Answer 4

• Nondisjunction – cells divide unequally
• Deletion – part or all of a chromosome is lost
• Translocation – part of one chromosome becomes detached and reattaches to a different chromosome

Question 5

What are the two most common clinical features in children with most genetic disorders involving the central nervous system?

Answer 5

hypotonia

mental retardation

Question 6

What principles of motor learning are important to use when working with children with cognitive impairment?

Answer 6

practice and repetition (the child with cognitive impairment takes longer to learn)

Also, breaking the task down into component parts improves the potential for learning the original task and for that task to carry over into other skills.

Question 7

What types of interventions are appropriate for a child with low tone?

Answer 7

• Weight bearing/Approximation – for stability and preparation for movement, postural alignment
• Movement transition – practice active trunk rotation, postural alignment, postural control against gravity
• Trunk extension, protective extension, balance reactions – for postural control against gravity
• Walking/Gait training with postural supports - to encourage mobility

Question 8

Name some secondary complications for children with low tone.

Answer 8

contractures
deformities
chest wall tightness
inefficient diaphragm

Question 9

What interventions can be used to prevent secondary complications in children with low tone?

Answer 9

interventions that work towards: 
normal alignment
maintenance of range of motion
typical weight bearing
postural control
general mobility

For example, facilitate normal postural alignment with use of splints to prevent hyperextension or facilitate upright posture to assist gravity to help the diaphragm form correctly.

Question 10

What interventions are most often used with a child with OI?

Answer 10

• Handling and positioning: Education of caregivers to pad all hard surfaces. They should carry the child on a pillow or in custom carrier, employ protective positioning, avoid pull-to-sit or grasping at ankles, ribs or shoulders. Employ positioning to avoid joint deformity
• Range of motion and strengthening: protected weight bearing, range of motion in straight plane, aquatic therapy – support limbs and encourage deep breathing
• Functional activities and gait: use safe, lightweight toys for motivation; encourage reaching; sitting in erect alignment (skip prop sitting) and sitting positions to being weight-bearing for LE; standing with sufficient support to avoid bending and bowing of LE long bones.

Above all, any interventions must be performed with an eye towards avoiding/preventing fracture.

Question 11

What physical therapy goal is most important when working with a child with a progressive genetic disorder?

Answer 11

keyword - progressive

keep the family Educated and Supported throughout child’s lifetime

Question 12

describe Rett Syndrome

Answer 12

x-linked
mutation in x-linked binding protein methyl-CpG-2
ataxia
mental retardation
growth retardation
almost always girls affected

hypotonia at birth
hypertonia and loss of acquired skills later
stereotypical hand movements - flapping, wringing, slapping, (and mouthing)

Question 13

describe Osteogenesis Imperfecta

Answer 13

OI
Autosomal Domininant
bone metabolism
normal cognition

4 types
I - mildest - mild to moderate fragility
II - most severe, lethal - in utero fractures
III - intermediate - progressive
IV - more severe than type I - moderately severe fragility

Question 14

describe Arthrogryposis Multiplex Congenita

Answer 14

AMC
chormosome 5 or autosomal domininant on chromosome 9
multiple joint contractures, misaligned joints
normal cognition

Question 15

describe Cystic Fibrosis

Answer 15

CF
autosomal recessive
chromosome 7
defect in exocrine glands; thick mucus
normal cognition

postural drainage

• retained secretions
• impaired ability to clear airways
• impaired exercise tolerance
• chest wall deformities
• nutritional deficits

Question 16

describe Cri-u-chat Syndrome

Answer 16

chromosome 5 (short arm deleted)
nervous system and mental retardation
- delayed psychomotor development
- hypotonia
- delayed development of postural reactions
- hyperextensible joints
- contractures, skeletal deformities
- impaired respiratory function

Question 17

describe Prader-Willi Syndrome

Answer 17

PWS
chromosome 15 (partial deletion)
prior to 2 years - won't eat
after 2 years - no full button
obesity, underdeveloped gonads, short stature, hypotonia
mild-moderate mental retardation
impaired respiratory function

instill good eating habits

Question 18

describe Spinal Muscular Atrophy

Answer 18

SMA
autosomal recessive
chromosome 5 (mutation)
Progressive
normal intelligence

3 types

• Werdnig-Hoffman - infantile SMA
• Type II - chronic or intermediate from of W-H - Chronic Childhood SMA - onset 2-18 mos
• Kugelberg-Welander - onset 2-15 years

PNS hypotonia
poor respiratory function
trunk muscle weakness
deformities

Question 19

describe Phenylketonuria

Answer 19

autosomal recessive
inborn error of metabolism - missing enzyme
preventable
- if not prevented, mental and physical developmental delays

Question 20

describe Fragile-X Syndrome

Answer 20

Martin-Bell Syndrome
leading cause of inherited mental retardation

mental retardation
unusual facies - long, narrow face with prominent forehead, jaw, ears
poor coordination
generralized decrease in muscle tone
enlarged tested in boys (after puberty) 

joint hypermobility
flatfoot
inguinal hernia
pectus excvatum
mitral valve prolapse

Question 21

define Mental Retardation

Answer 21

a substantial limitation in present function characterized by subaverage intelligence and related limitations in tow or more of the following areas:
communication
self-care
home living
social skills
community use
health and safety
academics
leisure
work

IQ less than 70-75

Question 22

What signs or symptoms would indicate respiratory or musculoskeletal deterioration in a child with DMD?

Answer 22

• Some signs of musculoskeletal deterioration include:
o The child develops severe lordosis, compensating for weakness of the quadriceps
o The child’s gate becomes lurching, and if the ankles do not have sufficient range to keep the feet plantigrade, dynamic balance becomes impaired.
o Gastrocnemius and TFL contractures
o Bilateral Trendelenburg signs would be indicative of hip abductor weakening.
• Some signs of respiratory deterioration include:
o Decreased oxygen saturation levels
o Recurrent pneumonia
o Chest wall tightness