Muscular Dystrophy, Limb-Girdle, Autosomal Recessive 5

Alternative Names

  • LGMDR5
  • Muscular Dystrophy, Limb-Girdle, Type 2C
  • LGMD2C
  • Muscular Dystrophy, Duchenne-Like
  • Duchenne-Like Muscular Dystrophy, Autosomal Recessive, Type 1; DMDA1
  • DMDA
  • Adhalin Deficiency, Secondary
  • Sarcoglycan, Gamma, Deficiency of
  • Severe Childhood Autosomal Recessive Muscular Dystrophy, North African Type; SCARMD
  • Maghrebian Myopathy

Associated Genes

Sarcoglycan, Gamma
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WHO-ICD-10 version:2010

Diseases of the nervous system

Diseases of myoneural junction and muscle

OMIM Number

253700

Mode of Inheritance

Autosomal recessive

Gene Map Locus

13q12.12

Description

Limb Girdle Muscular Dystrophies (LGMD) are a group of genetic muscular disorders of the voluntary muscles, especially the pelvic and shoulder girdles. Many different types of this disease condition are now known, all of which are caused by defects in different genes. LGMD Type 2C is an autosomal recessive condition caused by mutations in the gamma sarcoglycan gene. Like other LGMDs, this type also is characterized by weakness in the proximal muscles (pelvis, hips, upper legs, and shoulders), abnormal gait, loss of muscle mass, and joint contractures. However, the disease is usually more severe than other types of LGMDs. 

Molecular Genetics

LGMD2C is a sarcoglycanopathy, caused due to mutations in the gamma sarcoglycan (SGCG) gene. The sarcoglycan protein is a component of the sarcoglycan complex (made up of sarcoglycan alpha, beta, and delta, apart from gamma). The complex, in itself is an integral part of the dystrophin-glycoprotein complex, which lends structure and stability to the muscles. Mutation in any one of the sarcoglycan genes causes the absence of the corresponding subunit, and also leads to a secondary reduction in the other three glycoproteins. It is clear to see, therefore, how mutations in the SGCG gene could develop into the muscular dystrophy seen in LGMD2C.

Epidemiology in the Arab World

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Other Reports

Algeria

Azibi et al. (1993) identified 57 Algerian patients with 'severe childhood autosomal recessive muscular dystrophy' (SCARMD) linked to proximal part chromosome 13q. The patients belonged to 34 families, of which 29 had more than 1 affected member. They were the first to refer to this disorder as Maghrebian autosomal recessive myopathy.

[See also: Morocco > El Kerch et al., 1994].

Egypt

Ben Othmane et al. (1995) found that 6 Tunisian families and 1 Egyptian family with DMD-like muscular dystrophy showed linkage to the pericentromeric region of chromosome 13q (maximum lod score of 9.15 at D13S115). Ben Othmane et al. (1995) stated that the Egyptian family was the first non-North African family to be linked to the 13q locus.

[See also: Tunisia > Ben Othmane et al., 1995].

Kuwait

Farag (1989) reported a brother and sister with four sibs and four half sibs born to second-degree cousins of Kuwaiti origin. The patients demonstrated a clinical, biochemical, electro-myographic, and histopathological profile of pseudohypertrophic Duchenne muscular dystrophy with normal chromosome structure. The results sustained the perception of severe progressive limb-girdle muscular dystrophy with autosomal recessive inheritance. Initial research of DNA samples through cDNA probes from the Duchenne/Becker locus excluded the possibility of X-chromosome deletion. Farag (1989) stated that this disorder was found to be common within inbred Arab communities.

[Farag TI. Autosomal recessive Duchenne-like muscular dystrophy in Arabs, report of a Kuwaiti family and literature review. Med Prin Prac 1989; 1(2): 96-101.]

Lebanon

Nair et al. 2018 described a patient with muscular dystrophy and mildly elevated creatinine kinase. The patient exhbited an exon 7 deletion in the sarcoglycan gamma gene. 

Morocco

El Kerch et al. (1994) conducted linkage analysis in six families with autosomal recessive muscular dystrophy. They found linkage homogeneity to 13q in affected patients from Morocco, Tunisia, and Algeria; three Maghreb countries with a high frequency of the disorder. Statistical tests indicated the presence of a genetic homogeneity between the three Maghreb countries.

Vermeer et al. (2004) described a Moroccan patient (male) who presented with progressive walking disturbances for several years, exercise intolerance, and leg pains. Muscle biopsy revealed reduced expression of the sarcoglycans. Mutation screening of the SGCG gene identified a novel nonsense mutation in this patient: G93A (Trp31X) on exon 2. The patient was homozygous for this mutation.

Saudi Arabia

Salih et al. (1996) described the clinical and molecular features of 14 children (five males, nine females) with SCARMD seen in Saudi Arabia over a period of 10-years (1982-1993). Eleven of these patients were Saudis. Six of these 11 patients (three boys and three girls) belonged to two Saudi families; all six being born to consanguineous parents. Two other unrelated female Saudi patients had a history of the condition in their family, and had a total of six affected siblings. One other Saudi patient had a brother who had died early at the age of 15-years. In all the patients, symptoms first appeared between the ages of 3 and 9-years in the form of clumsy walking, frequent falling, and difficulty in running. Between the ages of 10 and 12-years, the children lost the ability to walk. At the time of the study, only nine of the 14 patients were walking. Of these, toe-walking was evident in two patients, one of them a Saudi. All 11 Saudi patients showed pseudohypertrophy of the calf muscles. Most patients attended normal school, and language function was found to be normal. EMG showed a myopathic pattern in all patients. Serum CK was increased (66-17,480 IU/L), ECG showed abnormalities, and muscle histology revealed abnormalities similar to Muscular Dystrophy. The oldest of the patients was a 16-year old Saudi female. She was completely dependent and was found to have congestive cardiomyopathy. Interestingly, she also had the lowest serum CK levels in the entire group (16 IU/L). A normal staining pattern for Dystrophin was obtained for all patients tested. However, two of the Saudi patients showed a specific deficiency of Adhalin. A third Saudi patient was also tested, but found to have normal Adhalin. Syntrophin and Dystroglycan levels were normal in these patients.

Sudan

Salih et al. (1983) reported a large Sudanese kindred of 176 individuals, of which 15 (seven boys and eight girls) members in the last three generation were affected with a severe form of autosomal recessive muscular dystrophy. Eight of these children (four boys and four girls) had died at the time of reporting. The disease had an onset before the age of 5-years in the form of weakness, and progressing steadily to a condition where the affected individual were unable to walk by the age of around 11-years in boys, and 13-years in girls. Female patients tended to survive longer, but all patients died at or before 20-years of age due to respiratory illness of short duration. The condition showed similarities with Duchenne muscular dystrophy in the selective distribution of muscle weakness seen, the age of onset of symptoms, and the rate of progression of the disease. However, the segregation ratio of 0.21 and the equal number of males and females affected suggested an autosomal recessive form of inheritance. In addition, serum CK levels were only mildly elevated (5 times the normal). Amplification and duration of QRS complexes were normal upon ECG, although the heart rate was abnormal (122 to 150 beats/minute) in five patients. Salih et al. (1983) concluded that the patients represented a variant of the Maghrebian Myopathy described in Tunisia and Libya. In 1984, Salih et al. reported results of further investigations on these patients. Pulmonary function and radiological investigations were carried out in the seven affected children who were alive. In all, Total Lung Capacity (TLC), Forced Vital Capacity (FVC), and Functional Residual Capacity (FRC) was found to be reduced (< 50-76%, < 31-55%, and < 51-88% of predicted values, respectively). Respiratory rate was found to be increased, with one child showing a rate of 42/minute. Since FEV1/FEC values were high, airway obstruction was excluded. Instead, these values confirmed that respiratory insufficiency was a major contributory factor in the mortality of the disease condition. Scoliosis was clear in only five of the children, and that too of a mild degree. Chest X-rays showed a clear field, removing any chance for the insufficiency to be due to atelectasis of the lung tissue. Salih et al. (1984) concluded that the disability was due to weakness of the respiratory muscle, and recommended that chest infections be treated vigorously in such patients to avoid a sudden decompensation.

Syria

Salih et al. (1996) described a Syrian family with two children (a 9-year old boy and a 5-year old girl) affected with SCARMD. The boy had a history of delayed walking, and at the time of reporting demonstrated toe-walking. On ECG, this patient showed sinus tachycardia, as well as several other cardiac irregularities. Altered QRS configurations hinted towards intraventricular conduction delays.

[See also: Saudi Arabia > Salih et al., 1996].

Tunisia

Ben Hamida et al. (1983) reported 93 children with a form of autosomal recessive, severe, progressive muscular dystrophy unusually frequent in Tunisia. Of the 93 cases, 75 came from 17 families with affected persons of both sexes and the other 18 came from 11 families with only girls affected. The 28 kindreds included 45 pairs of parents with myopathic children. Over three-fourths of the parental pairs were closely consanguineous, compared with consanguinity rates of 16 to 23% in the general population. The first clinical symptoms were noticed between 3 to 12 years and inability to walk occurred between ages 10 and 20. The serum creatine kinase was markedly raised in the early stages of disease. Muscle wasting affected mainly limb girdle and truncal muscles; calf muscle hypertrophy was usually present.

In 1990, Ben Jelloun-Dellagi and colleagues demonstrated that the dystrophin protein is normal in the Tunisian form of autosomal recessive muscular dystrophy.

Linkage studies by Ben Othmane et al. (1992) using three consanguineous families from Tunisia demonstrated that the DMD-like disease locus was situated on chromosome 13p; 2 markers within 13q12 showed a lod score of 9.15 and 8.4 at theta = 0.03. Later, Ben Othmane et al. (1995) found that 6 Tunisian families and 1 Egyptian family with DMD-like muscular dystrophy showed linkage to the pericentromeric region of chromosome 13q (maximum lod score of 9.15 at D13S115).

In 2 affected sibs from a Tunisian SCARMD family reported by Ben Othmane et al. (1992), Noguchi et al. (1995) identified a homozygous mutation in the SGCG gene. Noguchi et al. (1995) noted that the mutation not only affects gamma-sarcoglycan, but also disrupt the integrity of the entire sarcoglycan complex.

Fendri et al. (2006) studied an extended consanguineous family, in which a 21-year old male, born to consanguineous parents, presented with progressive pelvic muscle weakness since the age of 6-years. Upon examination, he was wheelchair-bound, had severe weakness of the lower limbs, calves hypertrophy, severely weak upper limb muscles, knee contractures, and ankle articulations. Serum analysis showed an abnormally high CK level of 1274 IU/l. Muscle biopsy showed a typical gamma sarcoglycanopathy staining pattern, with a total absence of gamma sarcoglycan, and relatively preserved staining of the other three sarcoglycans. Mutation analysis confirmed LGMD2C.

[See also: Morocco > El Kerch et al., 1994].

Yemen

Salih et al. (1996) described a Yemeni female patient, 11-years of age, who was affected with SCARMD. She was the only patient in the group who did not display pseudohypertrophy of the calf muscles. She also displayed very mild scoliosis. Sinus tachycardia was evident on ECG, along with altered QRS configurations, which suggested intraventricular conduction delays. Dystrophin staining was found to be normal. However, she had defective Adhalin protein and normal levels of Syntrophin and Dystroglycan.

[See also: Saudi Arabia > Salih et al., 1996].

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