P020A
Developmental Disabilities
Mrs. Elizabeth Keele, RN
Course Objective #23
• Identify the metabolic problem and the resulting
presentation in each of the following recessive
inheritance syndromes:
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Phenylketonuria
Galactosemia
Tay-Sachs Disease
Hurler Syndrome
Lesch-Nyhan Syndrome
Gaucher’s disease
Neimann-Pick Disease
Wilson’s Disease
Cretinism
Phenylketonuria
• AKA:
– PKU
• Gene on chromosome
12
– maybe 4 & 11
• Most common inborn
error of metabolism
• Incidence
– 1:10,000 in USA
– carrier 1:50
Phenylketonuria
• Cannot breakdown
phenylalanine 
– h phenylalanine 
– toxic to CNS
• Screening test
– Guthrie test
• Screening timeline
– After first 24 hrs. or
before 7-14 days
Phenylketonuria
Common Features
• Appear
– 7-10 days after birth
• ID
– if not treated early
• Blond & fair
• Musty odor
• Microcephaly
Phenylketonuria
Common Problems
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Vomiting
Irritability
Dry skin / Rash
Seizures
Phenylketonuria
Common Problems
• “Maternal PKU”
Phenylketonuria
Common Problems
• If noncompliant with
diet
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lower IQ
Learning disabilities
behavior problems
Tremors
Eczema
Impaired
communication
Phenylketonuria
Common Treatment
• TREATABLE!!!!
• Low-protein
/phenylalanine diet
• Monitor blood
phenylalanine levels
• Skin care
• Symptom tx
Phenylketonuria
Common Treatment
• Prevent maternal PKU
by
– adhering to diet
– three months
before/during pregnancy
Galactosemia
• Chromosome 9
• Missing liver enzyme
– can’t digest milkproducts
– Galactose
• Incidence
– 1:20,000-1:60,000 live
births
Glactosemia - Pathophysiology
• If an infant with
galactosemia is given
milk,
– Galactose
– Toxic levels
– Damage
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Liver
Brain
Kidneys
Eyes
Galactosemia
Common Features
• S&S appear quickly
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Vomiting
Jaundice
Lethargy
Irritability
Seizures
• ID is preventable
• S&S may be due
– E. coli.
Galactosemia
Common Problems
• Severe ID
– Aminoaciduria
– Amino acids in
blood
• Hepatomegaly
– Enlarged liver
• Ascites
• Hypoglycemia
If not treated…
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Cataracts
Cirrhosis of the liver
Death
Delayed speech
i ovarian failure
Intellectual disability
E. coli sepsis
Tremors and
uncontrollable motor
functions
Galactosemia
Common Treatment
• Galactose-free diet
– life-long
• Calcium supplements
Tay-Sach’s Disease
• Chromosome 15
• Incidence:
– 1:30 Jews
– 1:270 general population
Tay Sach’s
• Body lacks
Hexosamindase A
• h Ganglioside 
• Nerve and brain cell
destruction 
• Deathmosis
Tay-Sach’s Disease
Common Features
• Appear
– about 3-6 months
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Deaf & blind
i muscle tone
Irritable
Paralysis
Seizure
Tay-Sach’s Disease
Common Problems
• No cure or treatment
• Death by 5 yrs
Tay-Sach’s Disease
Common Treatment
• Supportive care
• Grief counseling
Hurler’s Syndrome
• AKA:
– Gargoylism
– Hunter’s
• Cannot breakdown
sugar molecule
– Glycosaminoglycans
Hurler’s Syndrome
Common Features
– h Muccopolysaccharides
/Glycosaminoglycans
– Symptoms appear
• “Normal” birth
• @ 2 yrs
Hurler’s Syndrome
Common Features
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Claw hand
i growth
Heart valve problems
Joint Disease
Thick, coarse facial
features
• ID - progressive
Hurler’s Syndrome
Common Problems
• Dwarfism &
kyphosis
• Deaf
• Corneal clouding
• Cardiac
• ID
Hurler’s Syndrome-Common
Treatment
• Supportive care
• Prognosis
– Poor
Lesch-Nyhan Syndrome
• AKA
– Hyperuricemia
– Lip-Biting Syndrome
• X-linked recessive
• Incidence
– 1:100,000 males
Lesch-Nyhan Syndrome
• Lack enzyme needed
to recycle purines 
• h uric acid
• S&S appear
– by 3-6 months
Lesch-Nyhan Syndrome- Common
Features
• h uric acid level
• Progressive ID
• Compulsive, selfdestructive behavior
Lesch-Nyhan Syndrome
Common Problems
• Gout
• Kidney stones
• Self-mutilation
– Lips, mouth, tongue,
fingers
Lesch-Nyhan Syndrome-Common
Treatment
• Rx to reduce uric acid
– Allopurinol
• Behavior modification
• Hydration
• Safe environment
Gaucher’s Disease
• Incidence
– 1:1,000 Jews
• Chromosome 1
• Various types
Gaucher’s Disease-Common Features
• Glucocerebroside (lipid)
accumulates in visceral
organs
• S&S appear
– Different ages
Gaucher’s Disease-Common Features
• Progressive neurological
deterioration
• Affects
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Liver
Spleen
Lungs
Bone marrow
Brain
Gaucher’s Disease-Common Problems
• Progressive neurological
problems
• ID
• Bone/joint pain
• Type I fatal
Gaucher’s Disease-Common Treatment
• Genetic
counseling
• Enzyme
replacement
therapy
Niemann-Pick Disease
• Gene on chromosome
11
• Incidence
– 1:450 Jews
– 1:100,000 gen. Pop.
• Can’t metabolize
sphingomyelin
Niemann-Pick Disease -Common
Features
• h Sphingomyelin
• Lipid storage
disease 
• Cell death &
organ failure
Niemann-Pick Disease -Common
Problems
• ID
• Progressive motor
skills loss
• Enlarged
liver/spleen 
– jaundice
• S&S r/t
– organs affected
Niemann-Pick Disease -Common
Treatment
• Supportive &
symptomatic
• Genetic
counseling
Wilson’s Disease
• Gene on
chromosome 13
• Can’t metabolize
– copper
• S&S appear
– 5 -35 yrs
Wilson’s Disease-Common Features
• h Copper
• Affects
–Liver
–CNS
–Kayser-Fleischer
rings
Kayser-Fleischer Rings
Wilson’s Disease-Common Treatment
• i Copper diet
• water supply
Congenital Hypothyroidism (Cretinism)
• AKA
– Congenital
Hypothyroidism
• absence/deficiency of
– thyroid hormone
• Early diagnosis critical
to prevent ID
• Dx tests:
– T3, T4, TSH
Congenital Hypothyroidism
(Cretinism)-Common Features
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Dwarfism
Large tongue,
Low metabolic rate
Intolerance to cold
Congenital Hypothyroidism
(Cretinism)-Common Problems
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ID
Poor feeding,
Constipation
Short
Congenital Hypothyroidism
(Cretinism)-Common Treatment
• Early dx
• Replace
– Thyroid hormone
Course Objective #24
• Describe features of the following
multiple etiology congenital
disorders:
–Cornelia de Lange Syndrome
–Laurence-moon syndrome
Cornelia de Lange Syndrome
• AKA
– Brachmann-de Lange
• R/T chromosome 3
Cornelia de Lange Syndrome-Common
Features
• Microcephaly
• Hirsutism
• Low birth weight
– failure to thrive
• Short stature
• ID –
– Severe
• Clinodactyly,
• Syndactyly
• Cleft palate
Cornelia de Lange Syndrome-Common
Problems
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ID
Self-mutilation
Behavior problems
Seizures
Cleft palate
Hearing loss & speech
delay
Cornelia de Lange Syndrome-Common
Treatment
• GH
• Communication
aides
• Special
education
• Behavior
modification
Laurence-Moon Syndrome
• Genes on chromosomes
– 11, 13, 15, 16
• Incidence
– :13,500 Arabs in Kuwait
– 1:160,000 gen. pop
Laurence-Moon Syndrome
Common Features
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Gen. obesity
Dwarfism
Skeletal defects
Progressive vision
problems
• Hypogenitalism
Laurence-Moon Syndrome-Common
Problems
• ID
• Blindness
• Kidney & cardiac
disorders
• Speech problems
• Syndactyly
• Polydactyly
Laurence-Moon Syndrome-Common
Treatment
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Diet
Visual aides
SLP
Kidney care
Surgery
– to remove extra
digits
Course Objective #25
• Differentiate between microcephaly
and macrocephaly
Microcephaly
• Causes
Microcephaly-Common Features
• Small head
Microcephaly-Common Problems
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ID
Strabismus
Hypertonia
Seizures
Behavior problems
Microcephaly-Common Treatment
• Early intervention
• Anticonvulsant
medication
Shunt
Megaloencephaly
• 1o
– no underlying disease
• 2o
– D/T metabolic D/O
• ID
– May be normal, MR or
>IQ
Megaloencephaly-Common
Features
• h brain weight
– > 1600 g
• Normal
– 1350-1400 g
• Deformed skull
Megaloencephaly-Common
Problems
• ID / DD
• Seizures
• Neuro deficits
Megaloencephaly-Common
Treatment
• Symptomatic
treatment
Course Objectives #27
• Explain the difference between
cultural-familial retardation and
psychosocial disadvantage
Cultural-Familial Retardation
• ID
– Mild
• No
– Physical disability
• D/T
– Environmental causes
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Poor prenatal care
Nutrition
Disease
Toxins
Psychosocial ID
• D/T
– psychosocial factors
– No organic cause
• Not reversible
• Abuse family
• Neglect family
Course #28
• Explain what is meant by a neural
tube defect and describe the
difference between the various
forms of this type of disorder.
Spinal Bifida
Pathophysiology
• Congenital Neural Tube
defect
• Incomplete closure of the
vertebrae
• 3 Levels
– Spina Bifida Occulta
– Meningocele
– Myelomeningocele
Spina bifida occulta
• Bones of the spine do not close
• But the spinal cord and meninges
remain in place
• And skin usually covers the defect
Meningocele
• Meninges protrude from the spinal
canal
• But the spinal cord remains in place
Myelomeningocele
• Both the spinal cord and the
meninges protrude from the spinal
canal
• Co-morbidity
–Hydrocephalus
Spinal Bifida
The Infant with
Myelomeningocele
• Myelomeningocele must have a
repair of the open neural tube.
Failure to repair may result in
serious infection which would
harm the developing infant
brain. After the repair, many
children require the insertion
of a device called a shunt to
divert the cerebral spinal fluid
to treat the hydrocephalus.
Spinal Bifida
Etiology
• Idopathic
• Folic acid deficiency
during pregnancy
– Esp 1st month
Spinal Bifida
Diagnosis
• Ultrasound
• h Alpha fetoprotein
Spinal Bifida
• What food contain folic
Acid?
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Greens
Asparagus
Broccoli
Cauliflower
Corn
Green Beans or Peas
Sweet Potato
Cabbage or Coleslaw
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Black Beans
Lentils
Peas
Peanuts
Course Content #29
• Identify non-genetic biological
causes of development disabilities
factors that are required
–Prenatally
–Perinatally
–Postnatally
Prenatal
• Toxic substances
• Infection
Perinatal
• Premature
• Birth injuries
– Deprived of O2
– Forceps
– Nuchal chord
Postnatal
• Brain damage:
– Infections
• Encephalitis
• Meningitis
– vaccinations
• mosquitoes
• Lead poisoning
– TBI
• Prenatal
– Toxic substances (drugs, alcohol)
– Infection
• Perinatal
– Delivery complications
• Postnatal
– Head Injury
– Infection