Table 4.

Recommended Evaluations Following Initial Diagnosis in Individuals with GAN-Related Neurodegeneration

System/Concern

Evaluation

Comment

Extent of
neurologic
involvement 		Complete neurologic exam
Assess LMN dysfunction: weakness, amyotrophy, sensory loss.
  • Assessment to incl cranial nerve dysfunction (See Ophthalmologic involvement in this table.)
  • Consider motor & sensory NCV to document a sensorimotor axonal pattern of neuropathy.
Assess UMN dysfunction: spasticity, Babinski signs, hyperreflexia.
Assess cerebellar motor dysfunction: gait & postural ataxia, dysmetria, dysdiadochokinesis, tremor, dysarthria, nystagmus, saccades & smooth pursuit.

Use standardized scale to establish baseline for ataxia (SARA, ICARS, or BARS). 1, 2

EEG & brain MRI (if not previously performed) if seizures are a concern
Motor disability
& ADL 		Orthopedics / physical medicine & rehab / PT / OT eval

To incl assessment of:

  • Gross motor & fine motor skills
  • Mobility, ADL & need for adaptive devices
  • Need for PT (to improve gross motor skills) &/or OT (to improve fine motor skills)
ID / Cognitive
decline 		Developmental assessment
  • To incl motor, adaptive, cognitive, & speech-language eval
  • Eval for early intervention / special education
Dysarthria Assessment by speech-language pathologist
Feeding
difficulty 		Gastroenterology / nutrition / feeding team eval
  • To incl eval of aspiration risk & nutritional status
  • Consider eval for gastrostomy tube placement in patients w/dysphagia &/or aspiration risk.
Ophthalmologic
involvement 		Complete eye exam

To assess:

  • Extraocular movement (re cranial nerve involvement & strabismus)
  • For evidence of optic atrophy: best corrected visual acuity, color vision, visual fields, visual evoked potentials, OCT, fundus exam
  • Need for visual aids
Neuroophthalmologic exam (if not performed as part of eye exam above)
  • Nystagmus (caused by cerebellar dysfunction)
  • Strabismus (caused by involvement of cranial nerves III, IV &/or VI)
Auditory nerve
involvement 		Exam by audiologist
Genetic
counseling 		By genetics professionals 3To inform patients & their families re nature, MOI, & implications of GAN-related neuropathy in order to facilitate medical & personal decision making
Family support
& resources 		Assess need for:

ADL = activities of daily living; ID = intellectual disability; LMN = lower motor neuron; MOI = mode of inheritance; OCT = optical coherence tomography; OT = occupational therapy; PT = physical therapy; UMN = upper motor neuron

1.

SARA = Scale for the Assessment and Rating of Ataxia; ICARS = International Co-operative Ataxia Rating Scale; BARS = Brief Ataxia Rating Scale

2.
3.

Medical geneticist, certified genetic counselor, certified advanced genetic nurse

From: GAN-Related Neurodegeneration

Cover of GeneReviews®
GeneReviews® [Internet].
Adam MP, Feldman J, Mirzaa GM, et al., editors.
Seattle (WA): University of Washington, Seattle; 1993-2024.
Copyright © 1993-2024, University of Washington, Seattle. GeneReviews is a registered trademark of the University of Washington, Seattle. All rights reserved.

GeneReviews® chapters are owned by the University of Washington. Permission is hereby granted to reproduce, distribute, and translate copies of content materials for noncommercial research purposes only, provided that (i) credit for source (http://www.genereviews.org/) and copyright (© 1993-2024 University of Washington) are included with each copy; (ii) a link to the original material is provided whenever the material is published elsewhere on the Web; and (iii) reproducers, distributors, and/or translators comply with the GeneReviews® Copyright Notice and Usage Disclaimer. No further modifications are allowed. For clarity, excerpts of GeneReviews chapters for use in lab reports and clinic notes are a permitted use.

For more information, see the GeneReviews® Copyright Notice and Usage Disclaimer.

For questions regarding permissions or whether a specified use is allowed, contact: ude.wu@tssamda.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.