Psychology Wiki

Genetic counseling: Angelman Syndrome-2

34,203pages on
this wiki
Add New Page
Talk0 Share

Assessment | Biopsychology | Comparative | Cognitive | Developmental | Language | Individual differences | Personality | Philosophy | Social |
Methods | Statistics | Clinical | Educational | Industrial | Professional items | World psychology |

Clinical: Approaches · Group therapy · Techniques · Types of problem · Areas of specialism · Taxonomies · Therapeutic issues · Modes of delivery · Model translation project · Personal experiences ·

Angelman Syndrome


  • Introduce myself
  • What are the major concerns that you would like to have addressed today?
  • Who referred you to genetics?
  • Outline session
    • obtain medical history and family history
    • Dr. Saal will come in and do physical exam
    • discuss condition and testing options
    • address specific concerns

Medical HistoryEdit

  • complete intake
    • seizures?
    • medications?
    • sleeping patterns?
    • communications skills?
    • hyperactivity?
    • developmental assessment?
    • services received?
    • unusual behaviors? laughter? generally happy?
    • problems with balance? walking?
    • MRI?
  • complete pedigree


  • 1/12,000-1/20,000

Clinical FeaturesEdit

  • Feature present in about 100% of patients
    • normal prenatal and birth history
      • normal birth weight and head circumference
      • no major birth defects
    • normal metabolic and hematologic profile
    • structurally normal brain on MRI
      • mild cortical atrophy or dysmyelination possible
    • delayed motor development
      • apparent by 6-12months
      • usually severe
    • speech impairment
      • usually < 1 or 2 words
      • receptive language better than expressive language
    • movement and balance disorder
      • abnormal gait
      • tremulous movements of limbs
    • Unusual behaviors
      • Frequent laughter and smiling/happy demeanor
      • Excitability
      • Hyperactivity
      • Short attention span
  • Features Present in more than 80% of patients
  • Microcephaly
    • caused by delayed head growth
    • present by age 2
  • Seizures
    • Beginning by age 3
  • Abnormal EEG
    • Characteristic large amplitude slow-spike waves
  • Features found in 20-80% of patients
    • Strabismus
    • Hypopigmentation of skin and eyes
    • Feeding problems in infancy
    • Wide mouth, wide spaced teeth
    • Increased sensitivity to heat
    • Sleep disturbances


  • Behavioral modification for undesirable/socially unacceptable behaviors
  • Medication for seizures
  • Generally do not receive medication for hyperactivity
  • Occupation therapy for fine motor control
  • Speech therapy focusing on nonverbal means of communication
  • Safe, confining bedroom for nighttime sleeplessness
  • Monitoring for onset of scoliosis


  • Caused by loss of maternal contribution of region 15q11-q13
    • 65-75% of patients have 3-5Mb interstitial deletion
    • 3-7% of patients have paternal uniparental disomy
    • 2-6% of patients have imprinting defect
    • 5-11% of patients have mutations in the UBE3A gene within this region
    • 11-20% of patients have another unknown cause

Molecular TestingEdit

  • DNA methylation analysis
    • 78% of patients with a deletion, uniparental disomy, or an imprinting defect are detected this way
    • further testing is required to distinguish between these types
      • FISH analysis can detect deletions (70% of patients)
      • DNA polymorphism testing can detect uniparental disomy
      • Patients with imprinting defects have 15q11-q13 polymorphisms from both parents
        • imprinting center defect characterization available on research basis only
  • UBE3A mutation analysis
    • 11% of patients with Angelman syndrome have identifiable mutations

Recurrence RisksEdit

  • Families Genetic Mechanism Risk to Siblings
    • 65-75% 3-5Mb deletion <1%
    • <1% unbalanced translocation as high as 50%
  • small interstitial deletion
    • 3-7% paternal uniparental disomy <1%
    • <1% uniparental disomy with approaching 100% Robertsonian translocation
    • 1-3% imprinting defect as high as 50% (if deletion in imprinting center mother has deletion)
    • 1-3% imprinting defect likely <1% without deletion
    • 11% UBE3A mutation as high as 50% if mother has deletion
    • 10-15% other unidentifiable cause most cases not familial (but could be as high as 50%)

Psychosocial IssuesEdit

  • Who is involved in care of patient?
  • What is the living situation?
  • How will having a diagnosis change care and management?
  • How will having a diagnosis affect you?
  • Are there concerns about recurrence risks?


  • Geneclinics: Angelman syndrome
  • Smith's Recognizable Patterns of Human Malformations
  • Clinical Genetics Lecture


The information in this outline was last updated in 2002.

Material obtained under GFDL Licence from

Heckert GNU white Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License."

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.

Also on Fandom

Random Wiki