Transthyretin amyloid polyneuropathy in France: A cross-sectional study with 413 patients and real-world tafamidis meglumine use (2009-2019)

OBJECTIVE

We aimed to describe characteristics of patients with ATTR variant polyneuropathy (ATTRv-PN) and ATTRv-mixed and assess the real-world use and safety profile of tafamidis meglumine 20mg.

METHODS

Thirty-eight French hospitals were invited. Patient files were reviewed to identify clinical manifestations, diagnostic methods, and treatment compliance.

RESULTS

Four hundred and thirteen patients (296 ATTRv-PN, 117 ATTRv-mixed) were analyzed. Patients were predominantly male (68.0%) with a mean age of 57.2±17.2 years. Interval between first symptom(s) and diagnosis was 3.4±4.3 years. First symptoms included sensory complaints (85.9%), dysautonomia (38.5%), motor deficits (26.4%), carpal tunnel syndrome (31.5%), shortness of breath (13.3%), and unexplained weight loss (16.0%). Mini-invasive accessory salivary gland or punch skin and nerve biopsies were most common, with a performance of 78.8-100%. TTR genetic sequencing, performed in all patients, revealed 31 TTR variants. Tafamidis meglumine was initiated in 156/214 (72.9%) ATTRv-PN patients at an early disease stage. Median treatment duration was 6.00 years in ATTRv-PN and 3.42 years in ATTRv-mixed patients. Tafamidis was well tolerated, with 20 adverse events likely related to study drug among the 336 patients.

CONCLUSION

In France, ATTRv patients are usually identified early thanks to the national network and the help of diagnosis combining genetic testing and mini-invasive biopsies.

Current clinical management of CIDP with immunoglobulins in France: An expert opinion

Treatment strategies in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) must be adapted on a case-to-case basis. Validated and reproducible tools for monitoring treatment response are required at diagnosis, when initiating treatment and throughout follow-up. A task force of French neurologists, experts in neuromuscular disease reference centers, was assembled to provide expert advice on the management of typical CIDP with intravenous immunoglobulins (Ig), and to harmonize treatment practices in public and private hospitals. The task force also referred to the practical experience of treating CIDP with Ig at the diagnostic, induction and follow-up stages, including the assessment and management of Ig dependence, and following the recommendations of the French health agency.

French recommendations for the management of adult & pediatric chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare autoimmune disorder of the peripheral nervous system, primarily affecting the myelin sheath. The pathophysiology of CIDP is complex, involving both humoral and cellular immunity. The diagnosis of CIDP should be suspected in patients with symmetrical proximal and distal motor weakness and distal sensory symptoms of progressive onset, associated with decreased/abolished tendon reflexes. Treatments include intraveinous immunoglobulins, steroids and plasma exchange, with usually an induction phase followed by a maintenance therapy with progressive weaning. Treatment should be rapidly initiated to prevent axonal degeneration, which may compromise recovery. CIDP outcome is variable, ranging from mild distal paresthesiae to complete loss of ambulation. There have been several breakthroughs in the diagnosis and management of CIDP the past ten years, e.g. discovery of antibodies against the node of Ranvier, contribution of nerve ultrasound and magnetic resonance imaging to diagnosis, and demonstration of subcutaneous immunoglobulins efficiency. This led us to elaborate French recommendations for the management of adult & pediatric CIDP patients. These recommendations include diagnosis assessment, treatment, and follow-up.

IVIg increases interleukin-11 levels, which in turn contribute to increased platelets, VWF and FVIII in mice and humans

The mechanisms of action of intravenous immunoglobulins (IVIg) in autoimmune diseases are not fully understood. The fixed duration of efficacy and noncumulative effects of IVIg in immune thrombocytopenia (ITP) and acquired von Willebrand disease (AVWD) suggest other mechanisms besides immunological ones. Additionally to the peripheral destruction of platelets in ITP, their medullary hypoproduction emerged as a new paradigm with rescue of thrombopoietin receptor agonists (TPO-RA). In an ITP mouse model, interleukin (IL)-11 blood levels increase following IVIg. IL-11 stimulates the production of platelets and other haemostasis factors; recombinant IL-11 (rIL-11) is thus used as a growth factor in post-chemotherapy thrombocytopenia. We therefore hypothesized that IVIg induces IL-11 over-production, which increases platelets, VWF and factor VIII (FVIII) levels in humans and mice. First, in an ITP mouse model, we show that IVIg or rIL-11 induces a rapid increase (72 h) in platelets, FVIII and VWF levels, whereas anti-IL-11 antibody greatly decreased this effect. Secondly, we quantify for the first time in patients with ITP, AVWD, inflammatory myopathies or Guillain-Barré syndrome the dramatic IL-11 increase following IVIg, regardless of the disease. As observed in mice, platelets, VWF and FVIII levels increased following IVIg. The late evolution (4 weeks) of post-IVIg IL-11 levels overlapped with those of VWF and platelets. These data may explain thrombotic events following IVIg and open perspectives to monitor post-IVIg IL-11/thrombopoietin ratios, and to assess rIL-11 use with or without TPO-RA as megakaryopoiesis co-stimulating factors to overcome the relative hypoproduction of platelets or VWF in corresponding autoimmune diseases, besides immunosuppressant.

Antibody- and macrophage-mediated segmental demyelination in chronic inflammatory demyelinating polyneuropathy: clinical, electrophysiological, immunological and pathological correlates

BACKGROUND AND PURPOSE

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a heterogeneous autoimmune disorder critically lacking diagnostic biomarkers. Autoantibodies to nodal and paranodal components have recently been described in a small subset of patients. Here, the diagnostic value of immune reactivity toward the myelin compartment was investigated.

METHODS

Ninety-four French CIDP patients were retrospectively studied. The reactivity toward the peripheral nerve was investigated. Sural nerve biopsies were examined by electron microscopy and immunofluorescence.

RESULTS

Twenty-one patients (22%) and three patients (3%) presented with a strong immunoglobulin G or immunoglobulin M reactivity respectively against the myelin compartment. The clinical, electrophysiological and morphological features were examined in nine of these patients for whom sural nerve biopsies were available. Seven patients were electrodiagnosed with definite CIDP, one with possible CIDP and one was unclassifiable but sural nerve biopsy argued for CIDP diagnosis. Electron microscopy of sural nerve biopsies demonstrated the presence of macrophage-mediated demyelination restricted to the internode in all nine patients. Immunolabelling for voltage-gated sodium channels, myelin and axonal markers confirmed the presence of segmental demyelination and of remyelination. The nodal and paranodal regions, however, were unaffected in these patients. Nerve conduction studies corroborated the multifocal and segmental profile, and seven patients showed increased duration of proximal (1.5-5.1 times) and/or distal (1.2-3.4 times) compound muscle action potential in at least two nerves.

CONCLUSION

Antibody- and macrophage-mediated demyelination appears responsible for conduction alterations in CIDP patients and nerve immunostaining assays may serve as a supportive diagnostic biomarker.

Implication of the SH3TC2 gene in Charcot-Marie-Tooth disease associated with deafness and/or scoliosis: Illustration with four new pathogenic variants

The autosomal recessive demyelinating form of Charcot-Marie-Tooth can be due to SH3TC2 gene pathogenic variants (CMT4C, AR-CMTde-SH3TC2). We report on a series of 13 patients with AR-CMTde-SH3TC2 among a French cohort of 350 patients suffering from all type of inheritance peripheral neuropathy. The SH3TC2 gene appeared to be the most frequently mutated gene for demyelinating neuropathy in this series by NGS. Four new pathogenic variants have been identified: two nonsense variants (p.(Tyr970*), p.(Trp1199*)) and two missense variants (p.(Leu1126Pro), p.(Ala1206Asp)). The recurrent variant p.Arg954* was present in 62%, and seems to be a founder mutation. The phenotype is fairly homogeneous, as all these patients, except the youngest ones, presented scoliosis and/or hearing loss.

Phenotypic spectrum of Charcot-Marie-Tooth disease due to LITAF/SIMPLE mutations: a study of 18 patients

BACKGROUND AND PURPOSE

Charcot-Marie-Tooth (CMT) 1C due to mutations in LITAF/SIMPLE is a rare subtype amongst the autosomal dominant demyelinating forms of CMT. Our objective was to report the clinical and electrophysiological characteristics of 18 CMT1C patients and compare them to 20 patients with PMP22 mutations: 10 CMT1A patients and 10 patients with hereditary neuropathy with liability to pressure palsies (HNPP).

METHODS

Charcot-Marie-Tooth 1C patients were followed-up in referral centres for neuromuscular diseases or were identified by familial survey. All CMT1A and HNPP patients were recruited at the referral centre for neuromuscular diseases of Pitié-Salpêtrière Hospital.

RESULTS

Two phenotypes were identified amongst 18 CMT1C patients: the classical CMT form ('CMT-like', 11 cases) and a predominantly sensory form ('sensory form', seven cases). The mean CMT neuropathy score was 4.45 in CMT1C patients. Motor nerve conduction velocities in the upper limbs were significantly more reduced in CMT1A than in CMT1C patients. On the other hand, the motor nerve conduction velocity of the median nerve was significantly lower in CMT1C compared to the HNPP group. Distal motor latency was significantly more prolonged in CMT1A patients compared to the CMT1C and HNPP groups, the latter two groups having similar distal motor latency values. Molecular analysis revealed five new LITAF/SIMPLE mutations (Ala111Thr, Gly112Ala, Trp116Arg, Pro135Leu, Arg160Cys).

CONCLUSIONS

Our study delineates CMT1C as mostly a mild form of neuropathy, and gives clinical and electrophysiological clues differentiating CMT1C from CMT1A and HNPP. Delineating phenotypes in CMT subtypes is important to orient molecular diagnosis and to help to interpret complex molecular findings.

Classifications of neurogenetic diseases: An increasingly complex problem

Neurodegenerative disorders represent a wide group of diseases affecting the central and/or peripheral nervous system. Many of these disorders were described in the 19th century, but our genetic knowledge of them is recent (over the past 25 years). However, the continual discovery of disease-causing gene mutations has led to difficulties in the classification of these diseases. For this reason, our present proposals for updating and simplifying the classification of some of these conditions (Charcot-Marie-Tooth diseases, distal hereditary motor neuropathies, hereditary sensory and autonomic neuropathies, hereditary spastic ataxias, hereditary spastic paraplegias and hereditary spastic ataxias) are expounded here.

Acute liver toxicity due to methylprednisolone: consider this diagnosis in the context of autoimmunity

The occurrence of corticosteroid-induced hepatitis is a rare event that has been recently described in the literature. We report the case of an acute cytolytic hepatitis in a patient treated with methylprednisolone for multiple sclerosis associated with an autoimmune thyroid dysfunction. After ruling out other etiologies, we concluded that the acute liver injury was due to steroids, and we analyzed the specific circumstances in the literature where methylprednisolone may have been responsible for acute hepatitis.

[What's new in immune-mediated neuropathies?]

Many papers have been published in the field of immune-mediated neuropathies in 2010. Various topics have been covered: diagnostic criteria and clinical forms, pain and its risk factors, clinical evaluation and new immunological markers. Additionally, as nerve biopsy is still useful for evaluating patients with peripheral neuropathy, French and international guidelines have been published. This paper aims to summarize recent discoveries in the field of immune-mediated neuropathies.

POEMS syndrome with prominent acute axonal lesions

Polyneuropathy is a common presenting component of POEMS syndrome whose symptoms are attributed to an overproduction of vascular endothelial growth factor (VEGF). We report two female patients with POEMS syndrome presenting as a severe predominantly axonal neuropathy. A nerve biopsy was performed for these patients; pathological data confirmed unusual numerous acute axonal lesions associated with other classical signs of POEMS syndrome. POEMS syndrome is usually associated with demyelinating neuropathy (and secondary axonal loss); however, prominent axonal neuropathy (with acute axonal lesions on nerve biopsy) can also be observed in this disease. These observations illustrate the heterogeneity of peripheral nervous system involvement in POEMS syndrome.

[Management of stroke in sub-Saharan Africa: current issues]

In sub-Saharan Africa, stroke is likely to present an increasingly important public health problem with a larger relative share of overall morbidity and mortality. Overall, sub-Saharan Health Care is characterized by a lack of human resources, lack of facilities for special investigations, and especially an absence of specific programs addressing the prevention of cardiovascular conditions. Current data on the epidemiology of stroke in sub-Saharan Africa, although sparse and fragmentary, indicate a comparatively high incidence of cerebral hemorrhage associated with high blood pressure, while ischemic stroke in black Africans still appears to be related primarily to small artery disease, HIV infection, and sickle cell disease. With urbanization, the role of large-vessel atherosclerosis is increasing. It is thus essential to coordinate government funding, health care professionals and development agencies to address this rising health problem. Access to health care needs to be better structured, and screening programs should be developed in order to identify and treat vascular risk factors. Improved training of health care professionals is also required in the areas of prevention, diagnosis and management of stroke. Implementation of best-practice recommendations for the management of stroke adapted to the specificities and resources of African countries would help rationalize the scarce resources currently available.

[Small fibre neuropathy in primary Sjögren syndrome]

PURPOSE

About forty percent of the patients with primary Sjögren's syndrome (pSS) experience chronic neuropathic pain with normal electrodiagnostic studies. Two previous studies suggest that chronic neuropathic pain in pSS is due to small fiber neuropathy (SFN). Quantification of epidermal nerve fiber density after skin biopsy has been validated to diagnose small fiber neuropathy.

METHODS

Skin biopsy was performed in 14 consecutive pSS patients (satisfying the american-european classification criteria) with chronic neuropathic pain and normal electrodiagnostic studies suggesting SFN.

RESULTS

Fourteen female pSS patients exhibited chronic neuropathic pain [burning sensation (n=14), prickling (n=4), dysesthesia (n=8)] with paroxystic exacerbations (n=10) and allodynia (n=13), for a mean period of 18.4±12.4 months. Neuropathic pain involved mostly hands and feet (n=13), with a distal (n=9) and leg (n=4) predominant distribution. Neurological examination disclosed normal deep tendon responses and absence of motor weakness (n=14). Small fiber neuropathy was confirmed by skin biopsy in 13 cases. Epidermal nerve fiber density was decreased in distal [(n=12), mean 3.5±1.7 fibers/mm (N>6.9)] and proximal site of biopsy [(n=9), mean 7.04±2.63 fibers/mm (N>9.3)].

CONCLUSION

Small fiber neuropathy is commonly responsible of chronic neuropathic pain in pSS. Prevalence, physiopathology and neurological evolution of such neuropathies still remain unknown.

[Albers-Schönberg's disease with ocular manifestation]

Albers-Schönberg's disease is a rare disease (one case in 100,000 inhabitants), asymptomatic in the majority of cases. It belongs to the four clearly individualized forms of human osteopetrosis and has an autosomal dominant transmission. It induces generalized osteosclerosis, and most symptoms result from complications such as fractures following mild injury, compression of cranial nerves, especially the optic nerve, by stenosis of extracranial ostia, but also osteomyelitis of the lower maxilla. The treatment of Albers-Schönberg's disease is disappointing and only symptomatic, although the responsible genetic anomaly was recently identified. We report here the case of a 54-year-old woman, whose diagnosis of the disease has been known since adolescence, who presented with unilateral loss of vision and perimetric deficit due to papilla edema resulting from stenosis of the optic canal and benign intracranial hypertension.

[Diagnostic strategy for chronic inflammatory demyelinating polyradiculoneuropathy. Recommendations of the French working group]

The diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) requires a careful clinical and neurophysiological evaluation, often completed by CSF analysis. In numerous cases, this diagnosis is straightforward and leads to rapid initiation of an immunomodulatory treatment. However, some patients are not diagnosed because of atypical clinical and/or neurophysiological features, and do not benefit from a potentially effective treatment. In this context, a working group was composed with the task of establishing recommendations on diagnostic strategies for CIDP in the main clinical situations where this diagnosis may be suspected. We have summarized these recommendations and tried to present them in the form of a decision-making algorithm.

Contribution of electron microscopy to the study of neuropathies associated with an IgG monoclonal paraproteinemia

A typical monoclonal IgG dysglobulinemia whether benign (monoclonal gammopathy of undetermined significance, MGUS) or malignant can give rise to peripheral neuropathy by damaging nerves. At first, neurotoxicity of the chemotherapy if the patient is treated must be ruled out in such cases. Indeed, a variety of other mechanisms have been described: endoneurial deposits of immunoglobulin, infiltration of the immunoglobulin within myelin sheaths, POEMS syndrome, deposits of amyloid, chronic inflammatory demyelinating polyradiculoneuropathy and infiltration of malignant cells. Ultrastructural examination of a nerve biopsy can be decisive in combination with routine histological and immunopathological examinations. Characterization of the mechanism of the neuropathy in a dysglobulinemic context is important as it governs therapeutic options, which in certain cases are particularly beneficial.

Pain as the presenting symptom of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

Numerous clinical forms of CIDP have been described, but pain is generally considered a rare or secondary sign. We describe here the clinical, electrophysiological and neuropathological characteristics of five patients with CIDP and pain as the main presenting symptom, and their course with treatment. Between January 2003 and December 2004, we selected five patients with prominent or isolated pain among 27 patients diagnosed with CIDP. All patients were subjected to clinical and electrophysiological examinations, and had a complete laboratory work up to exclude other causes of neuropathy. In view of the atypical clinical presentation, all five patients underwent nerve biopsy. There were two men and three women. The mean age at onset of neuropathy was 70+/-7.39 years. All patients initially presented with pain in the lower limbs associated with modest motor impairment (1 case), distal paresthesia (4 cases), cramps (1 case) and fatigue (2 cases). CSF was normal in three cases. On electrophysiological examination, three patients had nerve conduction abnormalities with subtle or clear signs of demyelination: three (case 1, 2 and 4) fulfilled the criteria of Rotta et al. and two (case 2 and 4) the criteria of both Nicolas et al and the INCAT group. Patients were all given symptomatic treatment and four patients received an immunomodulatory treatment, which was constantly effective. Pain may be a major and disabling symptom in patients with CIDP, so this diagnosis has to be considered in patients referred for a painful polyneuropathy. Moreover, immunomodulatory treatment has to be considered in such patients as symptomatic therapy may be ineffective.

Dixièmes Journées des Maladies du Système Nerveux Périphérique Quoi de neuf depuis 10 ans dans l’évaluation des neuropathies périphériques?

In the past ten years, clinical evaluation of peripheral neuropathy has greatly improved, thanks to the development and validation of new evaluation tools. Notably, new functional scales that may be used in clinical trials as well as in daily practice have emerged. This evolution is remarkable, but will necessitate considerable efforts from Neurologists in their clinical practice. In the field of electrophysiological examination, techniques have not evolved as much in the past ten years. However, interpretation of abnormal results leading to the diagnosis of immune mediated peripheral neuropathies has improved, allowing the development of new rationales for diagnostic strategies.

Polyneuropathy with demyelinating features in mixed cryoglobulinemia with hepatitis C virus infection

Peripheral neuropathy can arise from various mechanisms during hepatitis C virus (HCV) infection, mainly involving associated mixed cryoglobulinemia. The frequency of demyelinating polyneuropathy is probably underestimated in these patients. We report two cases of demyelinating polyneuropathy in HCV-infected patients. The first case concerned a 76-year-old woman followed for hepatitis C associated with a mixed cryoglobulinemia (type II), who developed a chronic progressive distal motor weakness and sensory disturbances concomitant with a raise in serum aspartate aminotransferase (GOT/AST) and alanine aminotransferase (GPT/ALT) levels. Other laboratory studies were normal except for a decrease in the hemolytic fraction of complement to 75 IU (n = 400-520). The second case was a 68-year-old woman followed for hepatitis C associated with a mixed cryoglobulinemia (type II), who had sensory disturbances in the lower limbs. Laboratory studies were otherwise unremarkable. Cerebrospinal fluid studies showed a normal protein content without pleocytosis in both patients. In both cases nerve conduction studies were suggestive of a mixed axonal and demyelinating sensorimotor neuropathy. Sural nerve biopsy showed segmental demyelination and severe loss of large myelinated fibers as well as some onion bulb formation in both cases. The two patients subsequently improved, the first with an antiviral treatment and the second with oral steroids.

[Inflammation and demyelinization: IgIV mode of action]

Immunoglobulins have a variety of actions in dysimmune disorders. In neurological conditions such as the dysimmune neuropathies and multiple sclerosis, immunoglobulins are thought to exert a twofold effect: an immunomodulating action and a positive action on remyelination. We outline well recognized immunomodulator actions including the suppression of antibody production and neutralization of pathogenic antibodies, action on T lymphocytes and endothelial cells, modulation of complement proteins, and modulation of the expression of Fc gamma receptors on the surface of macrophages. Along with these actions in dysimmune disorders of the central and peripheral nervous systems, recent studies have provided evidence for an action on remyelination. In cultures of oligodendrocytes or myelinating cocultures of rat embryo brains, we have noted a direct action of immunoglobulins (tégéline) on myelination of the central nervous system. Our investigations have also indicated that immunoglobulins have an action on myelination of the peripheral nervous system. We employed the experimental acute neuritis model as well as in vitro models such as cultures of embryonic dorsal root ganglia and isolated Schwann cells. Interestingly the typical IgM immunoglobulins seemed more active than typical IgG ones. This observation may prompt new therapeutic options.

Échelles fonctionnelles et neuropathies périphériques

The usefulness of functional scales has become clear in the past few years, to evaluate patients with dysimmune peripheral neuropathies. Functional scales which measure the real impact of the disease process in our patients will probably be increasingly used in future therapeutic trials. By contrast with neurological disorders leading to pure motor involvement, peripheral neuropathies are difficult to evaluate, due to their clinical polymorphism. However, efforts have been made in the past ten years in order to validate functional scales that may be routinely used by neurologists for dysimmune neuropathies. New scales will probably arise in the next few years, to be used in neuropathies from other causes. These scales will have to be strictly validated to be used in the daily medical practice.

Polyradiculonévrite inflammatoire démyélinisante chronique et atteinte du système nerveux autonome

INTRODUCTION

Involvement of the autonomic nervous system during Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) is rare. Localised hyperhydrosis and Claude Bernard Horner (CBH) syndrome have never been reported in patients with CIDP.

CASE REPORT

We report the case of a 65-year-old right handed man who presented with hyperhydrosis localised to the right hemithorax and hemiface and a left CBH syndrome. After an extensive workup, the patient was found to have CIDP as the only cause of autonomic nervous system involvement. The symptoms resolved slowly after three courses of intravenous immunoglobulins.

CONCLUSION

Signs of autonomic nervous system involvement can be observed in CIDP as in Guillain-Barré syndrome. This case report shows that immunomodulatory treatment can be effective against dysautonomia in CIDP.

Polyradiculonévrites inflammatoires démyélinisantes chroniques : stratégie diagnostique

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) comprises a group of dysimmune neuropathies easily diagnosed in more than half of the patients. Diagnosis is based on clinical, electrophysiological and biological clues. In some patients, diagnosis is unclear because of the debated value of the available clues. In such circumstances, dysimmune neuropathies may not be diagnosed, leading to insufficient treatment. This is an important category of patients because immunomodulatory drugs have proven efficacy. The CIDP spectrum includes a relatively wide range of diseases. Besides the easily recognized classic forms, there are many clinical variants, sometimes with a paucisymptomatic presentation leading to uncertain diagnosis. The French CIDP study group has established guidelines for diagnostic strategy in CIDP patients. The first part of this paper is devoted to the clinical aspects of the disease, classical forms and variants. In the second part, the results of electrophysiological studies are reported. In a third chapter, complementary examinations useful for diagnosis are discussed. The fourth chapter deals with the diagnostic strategy, discussed in relation to the different situations which may be encountered in clinical practice. details the technical modalities of appropriate electrophysiological studies and presents normal results together with those indicating demyelinating neuropathy. Nerve biopsy technique and results are given in appendix II.

The genetic causes of basal ganglia calcification, dementia, and bone cysts: DAP12 and TREM2

BACKGROUND

Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL), or Nasu-Hakola disease, is a presenile dementia associated with loss of myelin, basal ganglia calcification, and bone cysts. It is caused by recessively inherited mutations in two genes encoding subunits of a cell membrane-associated receptor complex: TREM2 and DAP12. The clinical course of PLOSL has not been characterized in a series of patients with TREM2 mutations.

METHODS

The authors compare neurologic and neuroradiologic follow-up data of six patients carrying TREM2 mutations with PLOSL due to defective DAP12 genes. The authors review the known mutations in these two genes.

RESULTS

Mutations in DAP12 and TREM2 result in a uniform disease phenotype. In Finnish and Japanese patients with PLOSL, DAP12 mutations predominate, whereas TREM2 is mutated more frequently elsewhere.

CONCLUSIONS

Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy should be considered in adult patients under age 50 years with dementia and basal ganglia calcification. Radiographs of ankles and wrists, and DNA test in uncertain cases, confirm the diagnosis.