Handbook of Genetic Counseling/Hypotonia - Developmental Delay
Hypotonia - Developmental Delay
Contracting
[edit | edit source]- Introductions, acknowledge prior contact
- Assess main concerns of patient
- Why are they visiting Genetics today?
- What do they hope to gain from the session?
- explore desire to have a diagnosis
- mother previously mentioned that they had come to terms with not having a diagnosis
- explore desire to have a diagnosis
- What do they hope to gain from the session?
- Overview of today's session
- Restate patient's concerns
- Medical history, family history, physical exam, genetics, recurrence risk, testing options and limitations
Pediatric Intake
[edit | edit source]- Family History
- any relatives with hypotonia? developmental delay or learning disabilities? MR? -- no to all
- history of infant deaths or miscarriages? birth defects? -- no
- diabetes? cancer? thyroid prolems? heart problems? respiratory problems? genetic conditions? -- no to all
- consanguinity? -- no
Differential Diagnosis
[edit | edit source]- Canavan disease
- autosomal recessive
- characterized by developmental delays by age 3-5 months, severe hypotonia involving "head lag", and inability to sit, walk, or speak
- hypotonia eventually changes to spasticity and help with feeding is necessary
- macrocephaly
- Testing
- urine analysis for concentration of N-acetylaspartic acid (NAA)
- increased in affected patients
- blood analysis for levels of aspartoacylase enzymatic activity
- often unmeasurable in affected patients
- urine analysis for concentration of N-acetylaspartic acid (NAA)
Myotonic Dystrophy
[edit | edit source]- autosomal dominant
- incidence of 1/20,000
- suspected in infants with hypotonia, facial muscle weakness, generalized weakness, club foot, and respiratory insufficiency or failure
- Mild -- characterized by cataract and mild myotonia
- Classic -- characterized by muscle weakness and wasting, cataracts, myotonia, cardiac conduction abnormalities
- Congenital -- hypotonia, severe generalized weakness at birth, often have respiratory problems and early death, MR common
- Testing
- DNA analysis is 100% sensitive
- detects an expansion of the CTG trinucleotide repeat in the DMPK gene (19q13)
- > 37 repeats is abnormal
- > 50 repeats are symptomatic
- > 1000 repeats often seen in congenital type
- DNA analysis is 100% sensitive
- Cerebellar Ataxia
- most types have onset in adulthood
- Spinocerebellar Ataxia 7 -- failure to thrive and loss of motor milestones, loss of vision
- Spinocerebellar Ataxia 8 -- common initial symptoms are scanning dysarthria with a characteristic drawn-out slowness of speech and gait instability, hyperactive tendon reflexes
- onset can be as early as one year old
- Testing -- CTA/CTG expansion in the SCA8 gene (13q21) can be detected via DNA analysis
- Aicardi syndrome
- X-linked dominant inheritance
- characterized by the partial or complete absence of the corpus callosum (the structure that links the 2 hemispheres of the brain), infantile spasms, mental retardation, and an ocular abnormality called lacunae (lesions) of the retina of the eyes
- may be associated with other brain defects such as microcephaly or porencephalic cysts (cerebrospinal fluid-filled cavities or gaps in the brain)
- onset generally begins between the ages of 3 and 5 months
- Myasthenia gravis (familial infantile)
- autosomal recessive
- characterized by respiratory and feeding difficulties in an infant
- absence or weakness of the ocular muscles is also characteristic
- Familial Dysautonomia
- characteristics include lack of tearing, emotional lability, paroxysmal hypertension, increased sweating, cold hands and feet, corneal anesthesia, erythematous blotching of the skin, and drooling
- the absence of the fungiform papillae of the tongue is also characteristic
- scoliosis is often severe and neuropathic joints of the Charcot type may develop
- Ashkenazi-Jewish heritage is common
Previous Testing
[edit | edit source]- chromosomal testing done previously -- results normal
Management and Treatment
[edit | edit source]Psychosocial Issues
[edit | edit source]- How important is a diagnosis to you?
- If the visit to Genetics does not result in a diagnosis, what will this mean to you?
- Are you worried about your child having a "label"?
- Financial concerns
- Support Network
- do attend meeting of "Mother of Special Children" each month
- support from family? friends? church?
- Educational concerns
Support Groups and Resources
[edit | edit source]- Mothers of Special Children
- www.mothersofspecialchildren.com
- meet the second Monday of each month at 7:30
- Hyde Park Bethlehem United Church
- Hyde Park and Madison Road
- Ohio Coalition for the Education of Children with Disabilities
- www.ocecd.org
- Director: Margaret Burley
- Co-Director: Lee Ann Derugen
- Executive Office
- 165 West Center Street, Suite 302
- Marion, OH 43302-3741
- Phone (740) 382-5452 or (800) 374-2806 (in Ohio)
- Fax (740) 383-6421
- E-mail: ocecd@gte.net
- March of Dimes Birth Defects Foundation
- 1275 Mamaroneck Avenue
- White Plains, NY 10605
- email: resourcecenter@modimes.org
- internet: http://www.modimes.org
- Tel: 914-428-7100 888-MODIMES (663-4637)
- Fax: 914-428-8203
References
[edit | edit source]- www.geneclinics.org (Canavan syndrome, Myotonic Dystrophy, Cerebellar Ataxia)
- Smith's Recognizable Patterns of Human Malformation
- OMIM #304050 (Aicardi syndrome), #254210 (Myasthenia gravis), #223900 (Familial Dysautonomia)
- National Institute of Neurological Disorders and Stroke
- Aicardi syndrome information page
http://www.ninds.nih.gov/health_and_medical/disorders/aicardi.htm
Notes
[edit | edit source]The information in this outline was last updated in 2002.