Clinical Guidance

No genotype-phenotype correlations have been identified: to date, intra- and interfamilial variability is consistently observed .

Source: GeneReviews — "SH3TC2-Related Hereditary Motor and Sensory Neuropathy"

Diagnostic Criteria

No consensus clinical diagnostic criteria for SH3TC2-related hereditary motor and sensory neuropathy (SH3TC2-HMSN) have been published.

Suggestive Findings

SH3TC2-HMSN should be suspected in individuals with the following clinical manifestations, nerve conduction velocities, neuropathology, and family history .

Clinical manifestations

• Early and severe scoliosis, the presenting sign in most individuals

• Neuropathy, usually developing in the first decade or adolescence, but occasionally manifesting as delay in onset of independent ambulation in early childhood

• Slowly progressive neuropathy, with some individuals becoming wheelchair dependent because of involvement of the proximal lower limbs

Motor nerve conduction velocities (MNCV) are in the range observed in demyelinating disease:

Source: GeneReviews — "SH3TC2-Related Hereditary Motor and Sensory Neuropathy"

Differential Diagnosis

See Charcot-Marie-Tooth Hereditary Neuropathy Overview.

Source: GeneReviews — "SH3TC2-Related Hereditary Motor and Sensory Neuropathy"

Management Guidelines

No clinical practice guidelines for SH3TC2-related hereditary motor and sensory neuropathy (SH3TC2-HMSN) have been published.

Evaluations Following Initial Diagnosis

To establish the extent of disease and needs in an individual diagnosed with SH3TC2-HMSN, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended.

Table 5.

Recommended Evaluations Following Initial Diagnosis in Individuals with SH3TC2-Related Hereditary Motor and Sensory Neuropathy

System/Concern | Evaluation | Comment

Growth

| Measure height, weight, head circumference. |

Neurologic

| Neurologic exam by child neurologist | Assessment for:

• Tone, weakness, atrophy, sensory loss, joint contractures

• Foot /or hand involvement

• Spine involvement

• Cranial nerve involvement

• Ataxia

• Gait stability using CMT Infant Scale1 or CMT Pediatric Scale2

• Pain w/attention to distinguishing between neuropathic mechanical pain

Spine/foot

deformities | By pediatric orthopedist to determine interventions needed |

Musculoskeletal

| Physical medicine rehab / PT/OT eval | To incl assessment of:

• Gross motor fine motor skills need for PT (to improve gross motor skills) /or OT (to improve fine motor skills)

• Need for AFOs, specialized shoes

• Mobility, ADL, need for adaptive devices/durable equipment

• Need for handicapped parking

By pediatric orthopedist | Assess amount progression of spinal curvature extent of foot deformities.

Development

| Developmental assessment |

Source: GeneReviews — "SH3TC2-Related Hereditary Motor and Sensory Neuropathy"

Clinical Guidance

Obesity is to be avoided because it makes walking more difficult. Medications that are toxic or potentially toxic to persons with Charcot-Marie-Tooth (CMT) disease comprise a range of risks ranging from definite high risk to negligible risk . See www.cmtausa.org for an up-to-date list. Anesthesia. Relatively few studies reported in the literature address risks of anesthesia in patients with CMT. No complications were observed after anesthesia in a large cohort followed in specialized consultation, but the advice of the anesthesiologist should be followed. See also CMT Overview.

• Although it had no adverse effects in 41 persons with CMT , use of succinylcholine for general anesthesia is usually contraindicated.

• Blockers of the neuromuscular junction should be used with caution.

• Local/regional anesthesia, especially epidural analgesia at childbirth, has been used without problems in CMT. This use of anesthesia should be discussed on a case-by-case basis with the anesthesiologist.

Source: GeneReviews — "SH3TC2-Related Hereditary Motor and Sensory Neuropathy"

Therapies Under Investigation

Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder

Source: GeneReviews — "SH3TC2-Related Hereditary Motor and Sensory Neuropathy"

Surveillance Guidelines

Table 7. Recommended Surveillance for Individuals with SH3TC2-Related Hereditary Motor and Sensory Neuropathy

Source: GeneReviews — "SH3TC2-Related Hereditary Motor and Sensory Neuropathy"