Carpal tunnel syndrome in inherited neuropathies: A retrospective survey

Late Onset of Severe Demyelinating Peripheral Neuropathy in a 62-Year-Old African American Woman

ABSTRACT

Hereditary neuropathies are typically associated with an early onset of symptoms, but same types of neuropathies may also manifest late, after the age 50 years. A 62-year-old African American woman presented with a 6-year history of gait unsteadiness and has been using a walker since the age 57 years after an unwitnessed fall. Gradual worsening of walking difficulties was later followed by decreased dexterity. The family history was negative for neuromuscular disorders, including neuropathy. On examination, the patient had both distal and proximal weakness with distal sensory loss to all modalities and hyporeflexia. Charcot Marie Tooth Examination Score was 12. Previous electrodiagnostic testing at the age 60 years showed severe sensorimotor demyelinating polyneuropathy with bilateral severe carpal tunnel syndrome. Genetic testing showed a homozygous pathogenic mutation in SH3TC2 gene (c.2860C>T; p.Arg954*), associated with CMT4C. CMT4C is the most common recessive demyelinating sensorimotor polyneuropathy and overall comprises 0.4%-1.7% of all patients with Charcot-Marie-Tooth disease. It is more common in French Canadians and Spanish Roma and in recent natural history study; only 1 of 56 patients was African American. This report demonstrates sporadic occurrence of CMT4C in other ethnic groups as well.

Neuromuscular manifestations of wild type transthyretin amyloidosis: a review and single center's experience

Transthyretin amyloidosis (ATTR) is a condition defined by accumulation of insoluble transthyretin amyloid deposits in multiple organs, especially in the peripheral nerve and heart muscle. ATTR may result from transthyretin mutations (variant ATTR or ATTRv) or may occur with normal transthyretin genotype (wild type ATTR or ATTRwt). ATTRwt was previously known as "senile amyloidosis" and causes cardiomyopathy which may lead to heart failure with a preserved ejection fraction, affecting predominantly elderly men. The exact prevalence of ATTRwt in the general population remains unclear, but its occurrence may be underestimated in women. It was observed that a proportion of ATTRwt cardiomyopathy patients may develop slowly progressing neuropathy that is milder and indolent in comparison with typical progressive neuropathy associated with ATTRv. Furthermore, the causality of neuropathy is often uncertain in patients with ATTRwt. Neuropathy symptoms, including distal sensory loss, unsteadiness and (neuropathic) pain are common in elderly patients with multiple potential causes, and as ATTRwt patients are typically older, relatively high prevalence of peripheral neuropathy is expected with frequent comorbidities. Relatively high prevalence of ATTRwt in elderly population contrasts few documented cases of neuropathy caused by ATTRwt, and there is uncertainty whether ATTRwt neuropathy is an infrequent occurrence or a significant manifestation of multisystemic ATTRwt. We review neurologic and musculoskeletal manifestations of ATTRwt and present clinical features of a single center cohort of ATTRwt patients with suspected peripheral neuropathy.

Hereditary neuropathy associated with liability to pressure palsies: a 24-year experience with carpal and cubital tunnel surgery

The aim of this single-centre retrospective study was to evaluate the outcomes of carpal tunnel release surgery in patients with hereditary neuropathy with pressure palsies (HNPP). The secondary aims were to identify prognostic factors for the outcome of carpal tunnel release and to assess the outcome of cubital tunnel release. Our primary hypothesis was postoperative improvement. In total, 18 patients (26 carpal tunnel releases) with at least one symptomatic carpal tunnel syndrome were included. At a median follow-up of 8.5 years, more than 73% of the patients were satisfied with the results. The visual analogue scale (0 to 10) for discomfort decreased by 2.2 points (p < 0.001). The Boston Carpal Tunnel Questionnaire symptom severity scale decreased by 1.3 points (p < 0.001). The decrease in the Functional Status Scale was not significant. No significant prognostic factor for outcome was identified. A total of 12 patients also underwent cubital tunnel release, and three patients underwent just this procedure (23 procedures). Despite the lack of preoperative data, cubital tunnel release provided encouraging results. Level of evidence: III.

Clinical trials in Charcot-Marie-Tooth disorders: a retrospective and preclinical assessment

Objective

This study aimed to evaluate the progression of clinical and preclinical trials in Charcot-Marie-Tooth (CMT) disorders.

Background

CMT has historically been managed symptomatically and with genetic counseling. The evolution of molecular and pathologic understanding holds a therapeutic promise in gene-targeted therapies.

Methods

ClinicalTrials.gov from December 1999 to June 2022 was data extracted for CMT with preclinical animal gene therapy trials also reviewed by PubMed search.

Results

The number of active trials was 1 in 1999 and 286 in 2022. Academic settings accounted for 91% and pharmaceutical companies 9%. Of the pharmaceutical and academic trials, 38% and 28%, respectively, were controlled, randomized, and double-blinded. Thirty-two countries participated: the United States accounted for 26% (75/286). In total, 86% of the trials were classified as therapeutic: 50% procedural (21% wrist/elbow surgery; 22% shock wave and hydrodissection therapy), 23% investigational drugs, 15% devices, and 11% physical therapy. Sixty-seven therapeutic trials (49%) were designated phases 1-2 and 51% phases 3-4. The remaining 14% represent non-therapeutic trials: diagnostic testing (3%), functional outcomes (4%), natural history (4%), and standard of care (3%). One-hundred and three (36%) resulted in publications. Phase I human pharmaceutical trials are focusing on the safety of small molecule therapies (n = 8) and AAV and non-viral gene therapy (n = 3). Preclinical animal gene therapy studies include 11 different CMT forms including viral, CRISPR-Cas9, and nanoparticle delivery.

Conclusion

Current CMT trials are exploring procedural and molecular therapeutic options with substantial participation of the pharmaceutical industry worldwide. Emerging drug therapies directed at molecular pathogenesis are being advanced in human clinical trials; however, the majority remain within animal investigations.

Phenotypes Associated With the Val122Ile, Leu58His, and Late-Onset Val30Met Variants in Patients With Hereditary Transthyretin Amyloidosis

BACKGROUND AND OBJECTIVES

Hereditary transthyretin amyloidosis (hATTR) is a rare autosomal dominant systemic disease with variable penetrance and heterogeneous clinical presentation. Several effective treatments can reduce mortality and disability, though diagnosis remains challenging, especially in the United States where disease is nonendemic. Our aim is to describe the neurologic and cardiac characteristics of common US ATTR variants V122I, L58H, and late-onset V30M at presentation.

METHODS

We conducted a retrospective case series of patients with a new diagnosis of ATTRv between January 2008 and January 2020 to characterize features of prominent US variants. The neurologic (examination, EMG, and skin biopsy), cardiac (echo), and laboratory assessments (pro b-type natriuretic peptide [proBNP] and reversible neuropathy screens) are described.

RESULTS

A total of 56 patients with treatment-naïve ATTRv with symptoms/signs of peripheral neuropathy (PN) or cardiomyopathy and confirmatory genetic testing presenting with Val122Ile (N = 31), late-onset Val30Met (N = 12), and Leu58His ATTRv (N = 13) were included. The age at onset and sex distributions were similar (V122I: 71.5 ± 8.0, V30M: 64.8 ± 2.6, and L58H: 62.4 ± 9.8 years; 26, 25, 31% female). Only 10% of patients with V122I and 17% of patients with V30M were aware of an ATTRv family history, while 69% of patients with L58H were aware. PN was present in all 3 variants at diagnosis (90%, 100%, and 100%), though neurologic impairment scores differed: V122I: 22 ± 16, V30M: 61 ± 31, and L58H: 57 ± 25. Most points (deficits) were attributed to loss of strength. Carpal tunnel syndrome (CTS) and a positive Romberg sign were common across all groups (V122I: 97%, 39%; V30M: 58%, 58%; and L58H: 77%, 77%). ProBNP levels and interventricular septum thickness were highest among patients with V122I (5,939 ± 962 pg/mL, 1.70 ± 0.29 cm), followed by V30M (796 ± 970 pg/mL, 1.42 ± 0.38 cm) and L58H (404 ± 677 pg/mL, 1.23 ± 0.36 cm). Atrial fibrillation was present among 39% of cases with V122I and only 8% of cases with V30M and L58H. Gastrointestinal symptoms were rare (6%) among patients with V122I and common in patients with V30M (42%) and L58H (54%).

DISCUSSION

Important clinical differences exist between ATTRv genotypes. While V122I is perceived to be a cardiac disease, PN is common and clinically relevant. Most patients with V30M and V122I were diagnosed de novo and therefore require clinical suspicion for diagnosis. A history of CTS and a positive Romberg sign are helpful diagnostic clues.

Carpal tunnel syndrome: updated evidence and new questions

Carpal tunnel syndrome is the most common entrapment neuropathy, affecting quality of life for many people. Although it is a well recognised condition, new insights into epidemiology, diagnosis, and treatment have emerged in the past 6 years. The availability of disease-modifying treatments for rare systemic disorders associated with carpal tunnel syndrome (eg, amyloidosis) should alert clinicians to these diagnostic possibilities. Besides clinical evaluation and electrophysiology, the role of ultrasonography as a diagnostic tool has been confirmed and new ultrasound techniques have been applied, the clinical use and feasibility of which require further investigation. Surgical and non-surgical interventions are beneficial for the treatment of carpal tunnel syndrome and several treatment options are now available, giving clinicians the possibility to choose the best approach for every patient. New diagnostic and therapeutic techniques require further validation.

Utility of carpal tunnel release and ulnar decompression in CMT1A and HNPP

INTRODUCTION/AIMS

Carpal and cubital tunnel syndrome (CTS, CuTS) are common among patients with hereditary neuropathy with liability to pressure-palsies (HNPP) and Charcot-Marie-Tooth-1A (CMT1A), and may impact quality of life. We aimed to evaluate the utility of nerve decompression surgeries in these patients.

METHODS

Medical records were reviewed for patients with PMP22 mutation confirmed in Mayo Clinic laboratories from January 1999 to December 2020, who had CTS and CuTS and underwent surgical decompression.

RESULTS

CTS occurred in 53.3% of HNPP and 11.5% of CMT1A, while CuTS was present in 43.3% of HNPP and 5.8% of CMT1A patients. CTS decompression occurred in 10-HNPP and 5-CMT1A patients, and CuTS decompression with/without transposition was performed in 5-HNPP and 1-CMT1A patients. In HNPP, electrodiagnostic studies identified median neuropathy at the wrist in 9/10 patients and ultrasound showed focal enlargements at carpal and cubital tunnels. In CMT1A, median and ulnar sensory responses were all absent, and the nerves were diffusely enlarged. After CTS surgery, pain, sensory loss, and strength improved in 4/5 CMT1A, and 6/10 HNPP patients. Of clinical, electrophysiologic and ultrasound findings, only activity-provoked features significantly correlated with CTS surgical benefit in HNPP patients (odds ratio=117.0:95% CI 1.94>999.99, p=0.01). One CMT1A and one HNPP patient improved with CuTS surgery while 2 HNPP patients worsened.

DISCUSSION

CTS symptom improvement post-surgery can be seen in CMT1A and (less frequent) in HNPP patients. CuTS surgery commonly worsened course in HNPP. Activity-provoked symptoms in HNPP best informed benefits from CTS surgery.

Elderly patients with suspected Charcot-Marie-Tooth disease should be tested for the TTR gene for effective treatments

BACKGROUND AND AIMS

Some hereditary transthyretin (ATTRv) amyloidosis patients are misdiagnosed as Charcot-Marie-Tooth disease (CMT) at onset. We assess the findings to identify ATTRv amyloidosis among patients with suspected CMT to screen transthyretin gene variants for treatments.

METHODS

We assessed clinical, cerebrospinal fluid, and electrophysiological findings by comparing ATTRv amyloidosis patients with suspected CMT (n = 10) and CMT patients (n = 489).

RESULTS

The median (interquartile range) age at onset of neurological symptoms was 69 (64.2-70) years in the ATTRv amyloidosis vs 12 (5-37.2) years in CMT group (Mann-Whitney U, p < 0.01). The proportion of patients with initial sensory symptoms was 70% in the ATTRv amyloidosis group vs 7.1% in CMT group (Fisher's exact, p < 0.01). The proportion of patients with histories of suspected chronic inflammatory demyelinating polyneuropathy (CIDP) were 50% in the ATTRv amyloidosis group vs 8.7% in CMT group (Fisher's exact, p < .01). Other measures and outcomes were not different between the two groups. Five of the six patients with ATTRv amyloidosis received treatment and survived.

INTERPRETATION

For effective treatments, the transthyretin gene should be screened in patients with suspected CMT with old age at onset of neurological symptoms, initial sensory symptoms, and histories of suspected CIDP.

Temporal evolution of nerve conduction study abnormalities in anti-myelin-associated glycoprotein neuropathy

BACKGROUND

A distal-predominant demyelinating symmetric pattern is most frequent in patients with neuropathy associated with anti-myelin-associated glycoprotein (MAG) antibodies. The literature however lacks longitudinal data to describe whether this is consistent over time.

METHODS

From the Ottawa Neuromuscular Center database, we identified 23 patients with both immunoglobulin M gammopathy and anti-MAG antibodies. For median, ulnar and fibular motor conduction studies, we analyzed distal latency and amplitude, negative peak duration, terminal latency index (TLI), and conduction velocity. For median, ulnar, sural, and superficial fibular sensory conduction studies, we analyzed distal latency and amplitude. Results were compared for the earliest and the latest data sets.

RESULTS

The mean time interval between the two assessment points was 6.5 years. Median and ulnar motor nerve conduction studies did not show a significant change for any of the parameters tested. There was disproportionate prolongation of median distal motor latency and reduction in TLI, compared to the ulnar nerve. Deep fibular motor conduction studies showed a marked reduction in amplitudes over time. Sensory potentials were recordable in the upper limb in less than 50% at the first study and less than 25% on the most recent study. There was an even larger attrition of recordable sural and superficial fibular sensory potentials.

CONCLUSIONS

Our results highlight the stability of median and ulnar motor conduction study results over a mean observation period of 6.5 years. In contrast, lower limb motor and all sensory potentials show a marked trend toward becoming unrecordable.

[Carpal tunnel syndrome: Rare causes and associated forms behind a common and stereotyped affection]

Carpal tunnel syndrome (CTS) is too common a condition not to daily interact with the practitioner, if only because of its entanglement to other pathologies, causal or chance association. The typical symptomatology, with hand paresthesia and morning pain upon waking, is related to a median nerve injury in the confined space of the carpal tunnel, more often by local inflammation and tenosynovitis of the finger flexors (repetitive activity of the hands). SCC may be secondary to situations (pregnancy) or conditions (edema, hypothyroidism…), which exaggerate the ordinary pathophysiology or cause deposits in the channel (amyloidosis, mucopolysaccharidoses, etc.). Otherwise, SCC is favored by all neuropathies that cause nerve fragility (especially diabetes). It is sometimes the first sign of these various affections of which it can allow early diagnosis. Electroneuromyographic examination (ENMG) is a key examination to confirm the diagnosis (slowing of sensitive and motor conduction of the median nerve through the carpal tunnel, due to local demyelination), to look for a predisposing neuropathy and for signs of seriousness (amplitude reduction of electrophysiological signals) that indicate axonal loss. In SCC forms with only slowed conduction without sign of seriousness, a splint or infiltration treatment may be attempted. If this medical treatment does not bring healing, or if there are signs of seriousness or unbearable pains, a decompression surgery is indicated. Whether it is performed traditionally or endoscopically, it provides fast relief, even immediate.

Carpal tunnel syndrome and associated symptoms as first manifestation of hATTR amyloidosis

Background

Hereditary transthyretin amyloidosis (hATTR) is associated with significant morbidity and mortality. Early diagnosis and treatment are essential to improve patient's outcome. Carpal tunnel syndrome (CTS) is a common complication of hATTR amyloidosis. However, because CTS is also common in the general population, we wanted to assess whether CTS, when associated with systemic manifestations, could help direct physicians to screen for TTR gene mutation and early diagnosis.

Methods

We reviewed the charts and interviewed the patients with hATTR seen between 2017 and 2018. We noted the details of CTS diagnosis, treatment, and other systemic features of the disease.

Results

Seventeen of the 23 patients studied had CTS. CTS was the first manifestation of the disease in 10 of 17 patients. On average, CTS symptoms occurred 10.4 years before their diagnosis of hATTR amyloidosis. In 6 of 10 patients with CTS, the following systemic symptoms were present as the first manifestation: erectile dysfunction, dysautonomia, polyneuropathy, exercise intolerance, and gastrointestinal and ocular symptoms.

Conclusion

CTS occurs in most patients with hATTR amyloidosis and frequently precedes the hATTR diagnosis. Most patients with CTS preceding hATTR diagnosis have systemic features. Recognizing systemic features at the time of CTS presentation may help in early diagnosis of hATTR amyloidosis.

A genome-wide association analysis identifies 16 novel susceptibility loci for carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a common and disabling condition of the hand caused by entrapment of the median nerve at the level of the wrist. It is the commonest entrapment neuropathy, with estimates of prevalence ranging between 5-10%. Here, we undertake a genome-wide association study (GWAS) of an entrapment neuropathy, using 12,312 CTS cases and 389,344 controls identified in UK Biobank. We discover 16 susceptibility loci for CTS with p < 5 × 10^-8. We identify likely causal genes in the pathogenesis of CTS, including ADAMTS17, ADAMTS10 and EFEMP1, and using RNA sequencing demonstrate expression of these genes in surgically resected tenosynovium from CTS patients. We perform Mendelian randomisation and demonstrate a causal relationship between short stature and higher risk of CTS. We suggest that variants within genes implicated in growth and extracellular matrix architecture contribute to the genetic predisposition to CTS by altering the environment through which the median nerve transits.