Handbook of Genetic Counseling/Hypotonia - Developmental Delay

Hypotonia - Developmental Delay Contracting 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 Overview of today's session Restate patient's concerns Medical history, family history, physical exam, genetics, recurrence risk, testing options and limitations Pediatric Intake 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 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 Myotonic Dystrophy 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 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 chromosomal testing done previously -- results normal Management and Treatment Psychosocial Issues 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 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 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 The information in this outline was last updated in 2002.