Biomedical subjects

N Birouk

Publications and source records attributed to N Birouk.

At least 19 recordsLinked to original sources

PubMed2006

Spine deformities in Charcot-Marie-Tooth 4C caused by SH3TC2 gene mutations.

BACKGROUND: Charcot-Marie-Tooth (CMT) disease is a heterogeneous group of inherited peripheral motor and sensory neuropathies with several modes of inheritance: autosomal dominant, X-linked, and autosomal recessive (AR) CMT. A locus responsible for the demyelinating form of ARCMT was assigned to the 5q23-q33 region (CMT4C) by homozygosity mapping. Recently, 11 mutations were identified in the SH3TC2 (KIAA1985) gene in 12 families with demyelinating ARCMT from Turkish, Iranian, Greek, Italian, or German origin. OBJECTIVE: To identify mutations in the SH3TC2 gene. METHODS: The authors searched for SH3TC2 gene mutations in 10 consanguineous CMT families putatively linked to the CMT4C locus on the basis of haplotype segregation and linkage analysis. RESULTS: Ten families had mutations, eight of which were new and one, R954X, recurrent. Six of the 10 mutations were in exon 11. Onset occurred between ages 2 and 10. Scoliosis or kyphoscoliosis and foot deformities were found in almost all patients and were often inaugural. The median motor nerve conduction velocity values (</=34 m/s) were not correlated with disease duration. The functional disability score was </=3, indicating that the patients could walk without help. Unexpectedly, typical giant axons were observed on biopsies from a large Algerian family. CONCLUSIONS: Charcot-Marie-Tooth type 4C (CMT4C) is less severe than other autosomal recessive (AR) CMT. Intrafamilial variability is important, making phenotype-genotype correlations difficult, but spine deformities are clearly a hallmark of CMT4C. In the presence of scoliosis, a neurologic examination is recommended. Giant axons on biopsies are also suggestive of CMT4C. For genetic analysis, the R954X mutation should be looked for before systematic sequencing of exon 11.

Charcot-Marie-Tooth Disease↗

PubMed2006

[Pseudoainhum and peripheral neuropathy].

BACKGROUND: Pseudoainhum is a rare disease characterised by gradual fibrous constriction of the fingers and/or toes eventually resulting in their amputation. In this article, we report the first case seen in Morocco, highly unusual in terms of its severity. CASE REPORT: A 46-year-old woman with no toxic habits was hospitalised for spontaneous amputation of the fingers and toes. This condition began when the patient was 12 years old with the appearance of a circular constriction band at the base of the fifth toe, eventually resulting in its loss. The patient gradually lost all her other toes and fingers except for the first joint of her left index finger. There was no family history of any similar condition. Clinical examination also revealed perforating plantar disease in two of the stumps and peripheral neuropathy in all four limbs, comprising predominantly axonal disease responsive to electromyogram. Amputation of the index finger was completed and histological examination of the removed section showed nothing unusual, with no signs of diabetes. DISCUSSION: The peculiarity of our case resides in the exceptional severity of these amputations and their association with isolated polyneuropathy. Pseudoainhum has been described chiefly in patients with congenital keratoderma, certain systemic diseases, diabetes and alcohol dependence. A number of etiopathogenic hypotheses have been suggested: traumatic, infectious, vascular, neurological and genetic processes.

Ainhum↗

PubMed2006

Autosomal-recessive forms of demyelinating Charcot-Marie-Tooth disease.

Autosomal-recessive forms of Charcot-Marie-Tooth (ARCMT) account for less than 10% of the families in the European CMT population but are more frequent in the Mediterranean basin and the Middle East because of more widespread consanguinity. Until now, demyelinating ARCMT was more extensively studied at the genetic level than the axonal form. Since 1999, the number of localized or identified genes responsible for demyelinating ARCMT has greatly increased. Eight genes, EGR2, GDAP1, KIAA1985, MTMR2, MTMR13, NDRG1, PRX, and CTDP1, have been identified and two new loci mapped to chromosomes 10q23 and 12p11-q13. In this review, we will focus on the particular clinical and/or neuropathological features of the phenotype caused by mutations in each of these genes, which might guide molecular diagnosis.

Cataract↗

PubMed2005

[Autonomic profile of patients with migraine].

OBJECT: Dysfunction of autonomic nervous system (ANS) is implicated in the genesis and persistence of migraine. The objective of this study was to compare autonomic nervous system (ANS) profile of migraineurs during headache-free periods to a group of normal subjects based on cardio-vascular reactivity. METHODS: Patients with migraine according to the criteria of IHS 2004 were selected for the study. After a 30 min resting blood pressure (BP), the following standard tests were performed: deep-breathing (DB), hand grip (HG) of 15 s and 3 min, valsalva maneuver, echo stress, (ES) and tilt test (TT). Results were compared to 44 normal subjects, age similar, 37 female, (84.1%) using the Student test, with P < 0.005 as significant. RESULTS: Thirty-two patients (27 female (84.38%), 16-51 years, mean 40.41 +/- 7.8) were studied. Twenty-two patients (69%) had systolic blood pressure below 94 mmHg and 25 patients (78%) had diastolic blood pressure below 60 mmHg. Compared to normal, migraineurs exhibited a significantly higher vagal response (P < 0.001) and a significantly lower alpha sympathetic response, central by using ES as well as peripheral by using HG of 3 min (P < 0.001). CONCLUSIONS: Autonomic cardiovascular reactivity of patients with migraine showed a vagal hyperactivity and a deficiency of the alpha sympathetic system. This leads to further studies with new therapeutical approaches.

Adolescent↗

PubMed2003

Mutations in MTMR13, a new pseudophosphatase homologue of MTMR2 and Sbf1, in two families with an autosomal recessive demyelinating form of Charcot-Marie-Tooth disease associated with early-onset glaucoma.

Charcot-Marie-Tooth disease (CMT) with autosomal recessive (AR) inheritance is a heterogeneous group of inherited motor and sensory neuropathies. In some families from Japan and Brazil, a demyelinating CMT, mainly characterized by the presence of myelin outfoldings on nerve biopsies, cosegregated as an autosomal recessive trait with early-onset glaucoma. We identified two such large consanguineous families from Tunisia and Morocco with ages at onset ranging from 2 to 15 years. We mapped this syndrome to chromosome 11p15, in a 4.6-cM region overlapping the locus for an isolated demyelinating ARCMT (CMT4B2). In these two families, we identified two different nonsense mutations in the myotubularin-related 13 gene, MTMR13. The MTMR protein family includes proteins with a phosphoinositide phosphatase activity, as well as proteins in which key catalytic residues are missing and that are thus called "pseudophosphatases." MTM1, the first identified member of this family, and MTMR2 are responsible for X-linked myotubular myopathy and Charcot-Marie-Tooth disease type 4B1, an isolated peripheral neuropathy with myelin outfoldings, respectively. Both encode active phosphatases. It is striking to note that mutations in MTMR13 also cause peripheral neuropathy with myelin outfoldings, although it belongs to a pseudophosphatase subgroup, since its closest homologue is MTMR5/Sbf1. This is the first human disease caused by mutation in a pseudophosphatase, emphasizing the important function of these putatively inactive enzymes. MTMR13 may be important for the development of both the peripheral nerves and the trabeculum meshwork, which permits the outflow of the aqueous humor. Both of these tissues have the same embryonic origin.

Adolescent↗

PubMed2003

High incidence of SMN1 gene deletion in Moroccan adult-onset spinal muscular atrophy patients.

Spinal muscular atrophy (SMA) is an autosomal recessive motor neuropathy characterized by selective degeneration of anterior horn cells of the spinal cord. Childhood SMA is divided into three types (I-III) on the basis of age of onset and severity. These disorders have been linked to the 5q13 region, where mutations in the Survival Motor Neuron 1 (SMN1) gene have been found in affected individuals. In the case of adult-onset SMA (type IV), on the other hand, reports of homozygous absence of SMN1 gene have been rare. We conducted deletion analysis of SMN and a neighboring gene, NAIP (neuronal apoptosis inhibiting protein). Among 54SMA patients (types I-IV), all of Moroccan origin, Exon 7 of the SMN1 gene was homozygously absent in 100% of type I, 90% of type II, 74% of type III and 80% of type IV SMA patients. Deletion of SMN1 exon 8 was detected in 100% of type I, 53% of type II, 53% of type III and 80% of type IV patients. NAIP exon 5 was homozygously deleted in 67% of type I, 32% of type II, 5% of type III and 20% of type IV SMA patients. Thirty control individuals who were studied had normal SMN1 and NAIP genes. Our results show a high incidence of SMN1 gene deletion in adult-onset SMA patients indicating that SMN1 is the autosomal recessive adult SMA-causing gene. While NAIP is commonly deleted in SMA, this is unlikely to affect disease severity; it was deleted in two adult SMA patients with mild phenotypes.

Adult↗

PubMed2003

[Acute Guillain-Barré-like polyradiculoneuritis revealing acute systemic lupus erythematosus: two case studies and review of the literature].

The involvement of the peripheral nervous system in systemic lupus erythematosus (SLE) is rare and is dominated by distal symmetric axonal polyneuropathy and multiple mononeuropathy. It usually occurs in late course of the disease. Acute polyradiculoneuropathy of Guillain-Barré syndrome type is very rare and can frequently constitute the first symptom of systemic lupus. We report two cases of acute inflammatory demyelinating polyradiculoneuropathy (AIDP) complicated by respiratory failure due to systemic lupus. In the first case, the pure motor AIDP was the first manifestation of the SLE. The outcome under prednisone treatment was dramatically good with regression of clinical deficit and normalisation of nerve conduction within one month and 12 months of treatment respectively. In the second case the AIDP occurred only one week after diagnosis of SLE and corticotherapy. It was a demyelinating sensory-motor neuropathy. Clinical improvement was obtained after two cures of intravenous gammaglobulin (IVIg). The normalisation of nerve conduction was obtained within 8 months. AIDP is a very rare complication of SLE, but it should be searched as an aetiology of Guillain-Barré syndrome associated to systemic clinical symptoms or to blood inflammation. Corticotherapy could be sufficient, but in some cases the addition of IVIg or plasmapheresis might be necessary.

Acute Disease↗

PubMed2002

[Acute meningomyelitis and polyradiculoneuritis disclosing systemic lupus erythematosus].

A 25-year-old male presented purulent meningitis associated with transverse myelitis. Spinal T2-weighted MRI showed a large spinal cord with an intramedullary high signal. Infection resolved with antibiotic therapy but spastic paraplegia persisted. Four months later, he developed a Guillain-Barré syndrome with clinical and biological signs of systemic lupus erythematosus. Final outcome was fatal despite corticosteroid and immunoglobulin treatment.

Acute Disease↗

PubMed2001

The frequency of 17p11.2 duplication and Connexin 32 mutations in 282 Charcot-Marie-Tooth families in relation to the mode of inheritance and motor nerve conduction velocity.

The 17p11.2 duplication and Connexin 32 (Cx32) mutations are the most frequent gene mutations responsible for Charcot-Marie-Tooth diseases. We classified 282 Charcot-Marie-Tooth families according to the median motor nerve conduction velocity of the index patient and the mode of inheritance, and screened them for 17p11.2 duplication and Cx32 mutations. Forty-seven percent of the Charcot-Marie-Tooth families had median motor nerve conduction velocity under 30 m/s (group 1), 15% between 30 and 40 m/s (group 2), and 28% over 40 m/s (group 3). Spinal Charcot-Marie-Tooth (group 4) was observed in 7% of the families. Modes of inheritance were not similarly represented among the different groups. The 17p11.2 duplication was detected in index patients of group 1 only, and accounted for 83% of the familial cases and 36% of the isolated cases. In contrast, 21 Cx32 mutations were detected to variable degrees in groups 1-3, but were most numerous by far in dominant families of group 2 (44%). This systematic approach was taken to estimate the frequency of 17p11.2 duplication and Cx32 mutations in the different Charcot-Marie-Tooth subgroups, in order to propose a practical strategy for molecular analysis.

Adult↗

PubMed2001

Clinical, electrophysiological and molecular genetic characteristics of 93 patients with X-linked Charcot-Marie-Tooth disease.

X-linked dominant Charcot-Marie-Tooth (CMTX) disease is a motor and sensory neuropathy caused by mutations in the connexin 32 (CX32) gene. In this study we report the clinical, electrophysiological and genetic features of 93 patients (41 males, 52 females) from 37 unrelated families with CMTX. Age at onset was 15.4 +/- 9.6 years in males (range 1-40 years) and 18.7 +/- 13.1 years in females (range 1-56 years) (P = 0.22) and the duration of disease at the time of examination was 18.3 +/- 14.6 years in males and 23.9 +/- 13.7 years in females (P = 0.11). Males were more severely affected than females, with significantly more frequent muscle weakness, amyotrophy, proprioception loss, upper limb areflexia and pes cavus. Females were more frequently asymptomatic, whereas high functional disability scores were more frequently encountered in males. The electrophysiological studies showed that motor nerve conduction velocities in CMTX females, but not males, were heterogeneous between nerves compared with Charcot-Marie-Tooth type 1A (CMT1A) patients and controls. The terminal latency index (TLI) for the median nerve was 0.37 +/- 0.08; it was similar in men and in women and a little higher than those observed in CMT1A and controls. The range of values for median TLI was wider in both male and female CMTX patients than in controls, but was similar to that of CMT1A patients, suggesting that motor conduction was relatively homogeneous within a given nerve. Twenty-seven different CX32 mutations, including missense (n = 23), nonsense (n = 2) and frameshift mutations (n = 1) and one entire deletion of the CX32 coding sequence, were observed in the 37 families. Four of these mutations are described for the first time. The phenotype of the patients, especially age at onset, is discussed in relation to the functional consequences of CX32 mutations, analysed in vitro in Xenopus oocytes and mammalian cells. CMTX patients with age at onset in the first decade mostly presented non-functional mutations, suggesting that the physiological consequences of the mutations affect age at onset in CMTX.

Adolescent↗

PubMed2000

Phenotypic and genetic study of a family with hereditary sensory neuropathy and prominent weakness.

We report the clinical and electrophysiological features of six members of a French family with a dominantly inherited motor and sensory neuropathy. Mean age at onset was 33.6 +/- 9.1 years. Mean age at examination was 55.5 +/- 13.3 years. Clinical presentation combined symptoms of hereditary sensory and autonomic neuropathy type I (HSAN-I) with prominent distal muscle weakness. Five male patients presented with sensory symptoms involving the distal part of the limbs, especially the legs. All but one had histories of trophic alterations, consisting of poorly healing foot ulcers. Muscle weakness and wasting were always present, often severe, and mainly affected dorsiflexion of the toes and feet. One obligate female carrier aged 65 was clinically asymptomatic. Electrophysiological findings were consistent with a distal axonal motor and sensory neuropathy. Results of linkage analysis excluded the Charcot-Marie-Tooth 2A (CMT2A) and CMT2B loci and suggested the possibility of a linkage to HSAN-I locus on 9q22.1-q22.3.

Adult↗

PubMed1999

Spectrum of clinical and electrophysiologic features in HNPP patients with the 17p11.2 deletion.

OBJECTIVE: To study the clinical and electrophysiologic features of a large series of carriers of the 17p11.2 deletion. BACKGROUND: The 17p11.2 deletion is associated in most patients with recurrent acute nerve palsies, which is the typical presentation of hereditary neuropathy with liability to pressure palsies (HNPP). Nevertheless, a few other phenotypes have been reported. METHODS: On the basis of clinical and electrophysiologic data, the authors conducted a retrospective study of 99 individuals with the 17p11.2 deletion referred to their neurogenetic department between 1993 and 1997. RESULTS: In addition to the typical presentation of HNPP, they describe five other phenotypes in 15 patients: recurrent positional short-term sensory symptoms, progressive mononeuropathy, Charcot-Marie-Tooth disease-like polyneuropathy, chronic sensory polyneuropathy, and chronic inflammatory demyelinating polyneuropathy-like, recurrent subacute polyneuropathy; and 14 asymptomatic patients. In all the deletion carriers, regardless of their phenotype and by the second decade, the authors found a characteristic, multifocal electrophysiologic neuropathy consisting of a diffuse increase in distal motor latencies contrasting with normal or moderately reduced motor nerve conduction velocities, a diffuse reduction in sensory nerve action potential, and multiple focal slowing of nerve conduction at the usual sites of entrapment. The key diagnostic criterion is a bilateral slowing of sensory and motor nerve conduction at the carpal tunnel with at least one abnormal parameter for motor conduction in one peroneal nerve. CONCLUSION: The authors confirm the clinical phenotypic heterogeneity of the 17p11.2 deletion and suggest that electrophysiologic examination is a reliable tool for screening suspected HNPP patients in its various clinical presentations.

Adolescent↗

PubMed1999

Vitamin E deficiency ataxia associated with adenoma.

Vitamin E is one of the most important lipid-soluble antioxidant nutrient. Severe vitamin E deficiency (VED) can have a profound effect on the central nervous system. VED causes ataxia and peripheral neuropathy that resembles Friedreich's ataxia. We report here a patient presenting this syndrome, but also a prolactin and FSH adenoma. Both the neurological syndromes and the adenoma regressed after treatment with alpha-tocopherol. Although, the presence of the prolactinoma in this patient may not be related to his vitamin E deficiency, alpha-tocopherol treatment seems to be beneficial and might usefully be tested in patients with hypophyseal secreting other forms of adenoma.

Adenoma↗

PubMed1999

Genetic, cytogenetic and physical refinement of the autosomal recessive CMT linked to 5q31-q33: exclusion of candidate genes including EGR1.

Charcot-Marie-Tooth disease is an heterogeneous group of inherited peripheral motor and sensory neuropathies with several modes of inheritance: autosomal dominant, X-linked and autosomal recessive. By homozygosity mapping, we have identified, in the 5q23-q33 region, a third locus responsible for an autosomal recessive form of demyelinating CMT. Haplotype reconstruction and determination of the minimal region of homozygosity restricted the candidate region to a 4 cM interval. A physical map of the candidate region was established by screening YACs for microsatellites used for genetic analysis. Combined genetic, cytogenetic and physical mapping restricted the locus to a less than 2 Mb interval on chromosome 5q32. Seventeen consanguineous families with demyelinating ARCMT of various origins were screened for linkage to 5q31-q33. Three of these seventeen families are probably linked to this locus, indicating that the 5q locus accounts for about 20% of demyelinating ARCMT. Several candidate genes in the region were excluded by their position on the contig and/or by sequence analysis. The most obvious candidate gene, EGR1, expressed specifically in Schwann cells, mapped outside of the candidate region and no base changes were detected in two families by sequencing of the entire coding sequence.

Base Sequence↗

PubMed1999

A locus for an axonal form of autosomal recessive Charcot-Marie-Tooth disease maps to chromosome 1q21.2-q21.3.

Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of disorders that affect the peripheral nervous system. Three loci are known for the autosomal dominant forms of axonal CMT (CMT2), but none have yet been identified for autosomal recessive axonal CMT (ARCMT2). We have studied a large consanguineous Moroccan ARCMT2 family with nine affected sibs. The onset of CMT was in the 2d decade in all affected individuals who presented with a severe motor and sensory neuropathy, with proximal muscle involvement occurring in some patients. After exclusion of known loci for CMT2 and for demyelinating ARCMT2, a genomewide search was performed. Evidence for linkage was found with markers on chromosome 1q. The maximum pairwise LOD score was above the threshold value of 3.00, for markers D1S514, D1S2715, D1S2777, and D1S2721, and it reached 6.10 at the loci D1S2777, D1S2721, and D1S2624, according to multipoint LOD-score analysis. These markers defined a region of homozygosity that placed the gene in a 4.4-cM interval. Moreover, a recombination event detected in an unaffected 48-year-old individual excludes the D1S506 marker, thereby reducing the interval to 1.7 cM. In addition, the P0 gene, an attractive candidate because of both its location on chromosome 1q and its role in myelin structure, was excluded by physical mapping and direct sequencing.

Adolescent↗

PubMed1999

Rigid spine syndrome. Two case-reports.

UNLABELLED: Rigid spine syndrome is characterized by massive spinal rigidity, usually most marked in the cervical region. Stiffness of the peripheral joints is sometimes present. We report two cases. Patient 1 was a 12-year-old boy diagnosed at three years of age with Duchenne's muscular dystrophy because of delayed onset of walking. Contracture of the Achilles tendons, flexion contracture of the elbows, and loss of motion of the cervical spine were the main findings during the current evaluation. Radiographs of the affected joints were normal. An electrocardiogram showed an incomplete left bundle branch block. Muscle enzyme activities were moderately elevated. A myopathic pattern was seen on the electromyogram. A muscle biopsy showed muscle fiber atrophy with peri- and endomysial fibrosis. Patient 2 was a 39-year-old man with a five-year history of isolated rigidity of the cervical spine thought to be due to a spondylarthropathy. Extension was the only movement possible at the cervical spine. The peripheral joints showed no motion range limitation. Findings were normal from radiographs of the spine and sacroiliac joints, an erythrocyte sedimentation rate determination, an electromyogram, and muscle enzyme activity assays. A muscle biopsy showed muscle fiber atrophy with peri- and endomysial fibrosis. DISCUSSION: Rigid spine syndrome is rare in rheumatological practice and can simulate a number of other muscle and joint diseases. Peri- and endomysial fibrosis may be strongly suggestive, although nonpathognomonic. Involvement of the heart governs the prognosis.

Adult↗

PubMed1998

The first de novo mutation of the connexin 32 gene associated with X linked Charcot-Marie-Tooth disease.

X linked Charcot-Marie-Tooth disease (CMTX) is a hereditary motor and sensory neuropathy caused by mutations in the connexin 32 gene (Cx32). Using the SSCP technique and direct sequencing of PCR amplified genomic DNA fragments of the Cx32 gene from a Moroccan patient and her relatives, we identified the first de novo mutation of the Cx32 gene, consisting of a deletion of a G residue at position 499 in the Cx32 open reading frame. This previously unreported mutation produces a frameshift at position 147 in the protein and introduces a premature stop codon (TAG) at nucleotide 643, which results in the production of a truncated Cx32 molecule. This mutation illustrates the risk of an erroneous diagnosis of autosomal recessive CMT, especially in populations where consanguineous unions are frequent, and its consequences for genetic counselling, which can be avoided by molecular analysis.

Adolescent↗

PubMed1998

X-linked Charcot-Marie-Tooth disease with connexin 32 mutations: clinical and electrophysiologic study.

OBJECTIVE: To relate X-linked Charcot-Marie-Tooth disease (CMTX) phenotypes to gender and type of neuropathy by the study of a large series of CMTX patients with proven Cx32 point mutations. BACKGROUND: CMTX is an X-linked form of Charcot-Marie-Tooth disease, caused by mutations in the connexin 32 gene. Males are usually more severely affected and have slower nerve conduction velocities than females. METHODS: Forty-eight patients from 10 families with Cx32 mutations were examined clinically and electrophysiologically. Mutations were characterized in index cases by automatic sequencing and detected in at-risk individuals by polymerase chain reaction (PCR)-restriction or single strand conformation polymorphism (SSCP) analysis. Two patients from different families had light and electron microscopy examination of a sural nerve biopsy. RESULTS: Males (n = 21) were more severely affected than females (n = 27), although six of the females were severely disabled. In the majority of males, the median motor nerve conduction velocity (MNCV) was between 30 and 40 m/s, whereas in females it ranged from 30 to normal values. Two children with mutation, a 6-year-old boy and a 7-year-old girl, were normal clinically and electrophysiologically. In most patients, the amplitude of motor nerve compound muscle action potentials (CMAP) was reduced in all nerves tested. MNCV was reduced as a function of the degree of axonal loss. A significant correlation was found between the decrease in CMAP amplitude and MNCV in the median, ulnar, and peroneal nerves. Sural nerve biopsies in one patient with a missense and one with a nonsense mutation both showed axonal neuropathy. CONCLUSION: Electrophysiologic and histologic findings support primary axonal neuropathy in CMTX with Cx32 mutations. Clinical and electrophysiologic data in males with different missense mutations in the of Cx32 gene differed significantly. Furthermore, males with a nonsense mutation (Arg22Stop) had earlier onset and a more severe phenotype than males with missense mutations.

Adolescent↗