Alain Lagueny

A new mutation of the lamin A/C gene leading to autosomal dominant axonal neuropathy, muscular dystrophy, cardiac disease, and leuconychia

The LMNA gene encodes two nuclear envelope proteins, lamins A and C, derived from alternative splicing. First identified in autosomal dominant Emery-Dreifuss muscular dystrophy (AD-EDMD),1 mutations in this gene are implicated in up to seven diseases including autosomal recessive EDMD (AR-EDMD),2 limb-girdle muscular dystrophy type 1B (LGMD1B),3 dilated cardiomyopathy with conduction defects (DCM-CD),4,5 autosomal dominant partial lipodystrophy of Dunnigan type,6 autosomal recessive axonal Charcot-Marie-Tooth disease (AR-CMT2),7 mandibuloacral dysplasia,8 and Hutchinson-Gilford progeria syndrome.9,10 In addition, some patients appear to have a combination of these different phenotypes11,12 or a clinical variant including skin abnormalities.13 To extend the clinical spectrum of laminopathies, we report a previously undescribed dominant missense mutation, E33D, identified in LMNA and clinically characterised by the combination of axonal neuropathy with myopathic features, cardiac disease including dilated cardiomyopathy, conduction disturbances and arrhythmia, and leuconychia. The LMNA gene is therefore the first gene implicated in both autosomal dominant and recessive forms of CMT2. The pedigree of a white family originating from the south west of France is shown in fig 1. The index case (II-5) and his affected daughter (III-13) were neurologically and cardiologically assessed by one of our team; only partial information was available for other affected members through questioning of patient III-13. The clinical features of all the affected members are shown in table 1. The results of nerve electrophysiological examination of patients II-5 and III-13 are shown in table 2. A muscle CT scan performed for patient II-5 showed wasting and marked fatty infiltration predominating in paraspinal, vasti, hamstring, and gastrocnemius muscles (fig 2). Fig 3 shows the fingernails of patients II-5 and III-13, exhibiting leuconychia. View this table: Table 1 Clinical features of the affected family members View this table: Table 2 Electrophysiological study of patients II-5 and III-13 Figure 1 Pedigree of the family. Arrow …

Combined nerve and muscle biopsy in the diagnosis of vasculitic neuropathy. A 16‐year retrospective study of 202 cases

Abstract  We reviewed 202 biopsies performed on patients with suspected vasculitic neuropathy, of which 24 Churg‐Strauss cases are studied separately. Specimens from the superficial peroneal nerve and peroneus brevis muscle were taken simultaneously by one incision. Without taking into account constitutional signs, systemic involvement was present in 131 patients, whereas the remaining 47 corresponded to non‐systemic patients with lesions limited to peripheral nervous system and adjoining muscles. Diagnosis of panarteritis nodosa or microscopic polyangiitis, according to the size of involved vessels, was attested by an infiltration of vessel walls by inflammatory cells associated with fibrinoid necrosis or sclerosis. Microvasculitis was diagnosed when inflammatory infiltration concerned small vessels with few or no smooth‐muscle fibers and without any necrosis. Microvasculitis was present in 11 of 46 non‐systemic cases, and this predominance is statistically significant. Isolated perivascular cell infiltrates in the epineurium were considered not significant but allowed the diagnosis of ‘probable vasculitis’ if associated with at least one of the following features: regenerating small vessels, endoneurial purpura, asymmetric nerve fiber loss, and/or asymmetric acute axonal degeneration. Necrotizing vasculitis was visible in 60 cases: in nerve (16 cases), in muscle (19 cases), and both (25 cases). Microvasculitis was present in 25 cases: in nerve (19 cases), muscle (four cases), or both (two cases). Moreover, granulomatous vasculitis was found in the nerve of one non‐systemic patient presenting also sarcoid granulomas in muscle. There were 24 ‘probable vasculitis’ and 68 negative cases. Muscle biopsy improved the yield of definite vasculitis by 27%.

Minimal tissue damage after stimulation of the motor thalamus in a case of chorea-acanthocytosis

Autopsy findings are reported from a patient with chorea-acanthocytosis treated for 2 years by deep brain stimulation (DBS) of the motor thalamus. Postoperative testing showed a progressive improvement in axial truncal spasms. Although relatively high currents were used for 2 years in this patient, postmortem analysis showed minimal tissue damage in the vicinity of the electrode tip. It is concluded that DBS has little impact on the surrounding tissues.

Chronic inflammatory demyelinating polyneuropathy: immunopathological and ultrastructural study of peripheral nerve biopsy in 42 cases.

The authors recently reexamined the peripheral nerve biopsies from 42 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). There were 27 males and 15 females, aged from 9 to 84 years, and 13 had relapses. No patient had vasculitis, monoclonal gammopathy, tumor, diabetes mellitus, Lyme disease, familial neuropathy, HIV, or any other immune deficiency. In the endoneurium, perivascular inflammatory cell infiltrates were present in only one case, but scattered histiocytes marked by KP1 on paraffin-embedded fragments were present in every case and there were no T-lymphocytes. At ultrastructural examination macrophage-associated demyelination was observed in 17 cases, of which 6 had relapses separated by intervals of several months or years. Axonal lesions without associated primary demyelination were observed in 4 cases and 3 of these had relapses. Thirty-two patients had mixed lesions of demyelination and axonal involvement. This study confirms other recent data indicating that in all cases of CIDP, macrophages are present in the endoneurium. Macrophage-associated demyelination is the characteristic feature of demyelinating forms. On the other hand, isolated primary axonal forms, which have been known since 1989, are relatively frequent and prone to relapses.The authors recently reexamined the peripheral nerve biopsies from 42 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). There were 27 males and 15 females, aged from 9 to 84 years, and 13 had relapses. No patient had vasculitis, monoclonal gammopathy, tumor, diabetes mellitus, Lyme disease, familial neuropathy, HIV, or any other immune deficiency. In the endoneurium, perivascular inflammatory cell infiltrates were present in only one case, but scattered histiocytes marked by KP1 on paraffin-embedded fragments were present in every case and there were no T-lymphocytes. At ultrastructural examination macrophage-associated demyelination was observed in 17 cases, of which 6 had relapses separated by intervals of several months or years. Axonal lesions without associated primary demyelination were observed in 4 cases and 3 of these had relapses. Thirty-two patients had mixed lesions of demyelination and axonal involvement. This study confirms other recent data indicating that in all cases of CIDP, macrophages are present in the endoneurium. Macrophage-associated demyelination is the characteristic feature of demyelinating forms. On the other hand, isolated primary axonal forms, which have been known since 1989, are relatively frequent and prone to relapses.

Crow-Fukase (POEMS) syndrome: a study of peripheral nerve biopsy in five new cases.

Abstract  The pathogenesis of Crow–Fukase (POEMS) syndrome is not well known, and in some cases, a definite diagnosis is difficult to establish. Nerve fibers have been studied in about 120 peripheral nerve biopsies (PNBs), and a mixture of axonal and demyelinating lesions were found in most of them. We report five new cases of Crow–Fukase (POEMS) syndrome with ultrastructural examination of their PNBs. In every case, there were features of axonal degeneration and primary demyelination. Interestingly, uncompacted myelin lamellae (UMLs) were present in every case at a percentage of 1–7. The association of UML and Crow–Fukase (POEMS) syndrome was described 20 years ago but was only reported in a few studies and found in 31 of 41 cases. In fact, this association is very significant because apart from Crow–Fukase (POEMS) syndrome, UMLs can only be found with such a frequency in rare cases of Charcot–Marie–Tooth disease type 1B. UML was also reported in acute and chronic inflammatory demyelinating polyneuropathies but at a much lower percentage. Moreover, in our five cases, UML was frequently associated with a decrease in the number of intra‐axonal filaments, and this finding raises the problem of relationships between myelin formation and neurofilaments. So far, glomeruloid hemangiomas present in the dermis of some patients are considered as the only specific criteria of Crow–Fukase (POEMS) syndrome, but we think UML can also be regarded as highly suggestive of this entity on condition that a thorough ultrastructural examination of a PNB is performed.

Peripheral neuropathy associated with mitochondrial disorders: 8 cases and review of the literature

Abstract  Forty‐three cases of peripheral neuropathy (PN) have been reported in the literature with a proven mitochondria (mt) DNA mutation, and 21 had a peripheral nerve biopsy (PNB). We studied 8 patients, 1 of whom had severe sensory PN, 3 mild PN, and 4 subclinical PN. Nerve biopsy was performed in every case; all patients showed axonal degeneration and 4 showed features of primary myelin damage. In addition, there were 2 crystalline‐like inclusions in the Schwann cell cytoplasm of a patient with MERRF, and 1 in a patient with multiple deletions on the mtDNA. There are 11 cases of PNB in the literature with axonal lesions, 5 with demyelination, and 4 with mixed lesions. One PNB was not modified. A few crystalline‐like inclusions were seen in 1 case of MERRF. Such inclusions were first reported in the Schwann cell cytoplasm of unmyelinated fibers in a patient with Refsum disease and were considered to be modified mitochondria. However, their mitochondrial origin remains debatable.

Waldenström's macroglobulinemia and peripheral neuropathy: Deposition of M‐component and kappa light chain in the endoneurium

Some cases of peripheral neuropathy associated with benign IgM monoclonal gammopathy, or Waldenstroms macroglobulinemia, are probably of autoimmune origin; in some cases, anti-IgM serum reacts with the myelin sheaths of peripheral nerves. However, mechanisms may differ in other cases. In one case of neuropathy with macroglobulinemia, we found deposits of IgM immunoglobulin in the endoneurium. On ultrastructural examination, the deposits had erased the basement membrane of some nerve fibers that showed damage of both myelin and axon.

Inflammatory demyelination in a patient with CMT1A

We report a case of Charcot‐Marie‐Tooth disease (CMT), with identified PMP22 gene duplication (CMT type 1A), and with evidence of an inflammatory demyelinating process superimposed on the course of the chronic genetic disease. Macrophage‐associated demyelination was observed on the peripheral nerve biopsy. This observation supports some experimental data from the literature and shows that there may be a genetic susceptibility to inflammatory demyelinating processes in certain CMT kindreds. Muscle Nerve 28: 373–376, 2003

Amyloid neuropathy: a retrospective study of 35 peripheral nerve biopsies

Abstract  We performed a retrospective study of 35 peripheral nerve biopsies (PNBs) with amyloid deposits in the endoneurium. In every case, nerve lesions were studied on paraffin‐embedded fragments (PEFs) and by ultrastructural examination (USE). In addition, muscle fragments were taken and embedded in paraffin. Immunohistochemistry was performed with anti‐transthyretin (TTR) serum on 19 nerve and 15 muscle PEFs. Direct immunofluorescence with anti‐light‐chain sera was performed on frozen nerve fragments in 19 cases. Endoneurial amyloid deposits were easily identified on routine PEF in 26 cases, after Congo red or thioflavine staining in three, and by USE in six. A dramatic myelinated fiber loss was evidenced in 34 cases (77–2970 per mm2), and features of axonal degeneration were present in every case. Segmental demyelination was observed in 10 cases. A mutation in the TTR gene was present in 14 cases, with Met30 mutation in 10 and Ala49 in four members of the same family. Amyloid deposits were strongly marked by the anti‐TTR serum in 11 other cases, twice in the endoneurium, five around muscle fibers, and four in both locations. In eight patients, light‐chain positivity was evidenced in endoneurial deposits, lambda in six and kappa in two. Two other patients with monoclonal gammopathy did not present any light‐chain fixation. In 17 cases, amyloidosis was disclosed by PNB and 13 had a TTR pathology; eight of them, over 65 years old, correspond to a late‐onset form of familial amyloid polyneuropathy which is an underdiagnosed condition.

Peripheral neuropathy with essential mixed cryoglobulinemia: biopsies from 5 cases.

SummaryEssential mixed cryoglobulinemia, which can cause hypersensitivity vasculitis, was observed in five patients with peripheral neuropathy. Three cases presented with multifocal neuropathies and two cases with symmetrical polyneuropathy. One had cryoglobulinemia with IgM monoclonal gammopathy and IgG polyclonal gammopathy, and the other four had cryoglobulinemia with polyclonal gammopathy. Biopsies showed perivascular infiltration by mononuclaer cells around medium, and mainly small-sized blood vessels. This was observed in the epineurium (five cases) and muscular fragments (three cases). At ultrastructural examination two cases showed severe damage of most myelinated fibers, which presented acute stages of Wallerian-like degeneration, and the three other cases showed a less widespread destruction of myelinated fibers. Most endoneurial capillaries showed swollen endoneurial cells. Myelino-axonal degeneration of myelinated fibers is probably due mainly to the vasculitis always present in the epineurium. This damage was probably worsened by the modifications of endoneurial capillaries. These lesions and their mechanisms are quite different from those observed in cases of cryoglobulinemia with an isolated monoclonal gammopathy.