title: Sarcolemmal alpha and gamma sarcoglycan protein deficiencies in Turkish siblings with a novel missense mutation in the alpha sarcoglycan gene.
abstract: BACKGROUND
  The sarcoglycan alpha gene, also known as the adhalin gene, is located on chromosome 17q21; mutations in this gene are associated with limb-girdle muscular dystrophy type 2D. We describe two Turkish siblings with findings consistent with limb-girdle muscular dystrophy type 2D. The evaluation excluded a dystrophinopathy, which is the most common form of muscular dystrophy.
  
  
  METHODS
  Both siblings had very high levels of creatinine phosphokinase and negative molecular tests for deletions and duplications of the dystrophin gene. The older boy presented at 8 years of age with an inability to climb steps and an abnormal gait. His younger brother was 5 years old and had similar symptoms. The muscle biopsy evaluation was performed only in the older brother.
  
  
  RESULTS
  The muscle biopsy showed dystrophic features as well as a deficiency in the expression of two different glycoproteins: the alpha sarcoglycan and the gamma sarcoglycan. Sarcolemmal expressions of dystrophin and other sarcoglycans (beta and delta) were diffusely present. DNA analysis demonstrated the presence of previously unknown homozygous mutations [c.226 C > T (p.L76 F)] in exon 3 in the sarcoglycan alpha genes of both siblings. Similar heterozygous point mutations at the same locus were found in both parents, but the genes of beta, delta, and gamma sarcoglycan were normal in the remaining family members.
  
  
  CONCLUSIONS
  We describe two siblings with limb-girdle muscular dystrophy type 2D with a novel missense mutation. These patients illustrate that the differential diagnosis of muscular dystrophies is impossible with clinical findings alone. Therefore, a muscle biopsy and DNA analysis remain essential methods for diagnosis of muscle diseases.
authors.affiliation: Basic Oncology, Associate Professor in Pathology, Tepecik Research Hospital, Izmir, Turkey. Electronic address: agdiniz@gmail.com.
authors.forename: Gulden
authors.initials: G
authors.lastname: Diniz
authors.affiliation: Pathology Department, Dr. Behcet Uz Children's, Research Hospital, Izmir, Turkey.
authors.forename: Hulya
authors.initials: H
authors.lastname: Tosun Yildirim
authors.affiliation: Pediatric Neurology Department, Dr. Behcet Uz Children's, Research Hospital, Izmir, Turkey.
authors.forename: Gulcin
authors.initials: G
authors.lastname: Akinci
authors.affiliation: Medical Genetics Department, Dr. Behcet Uz Children's, Research Hospital, Izmir, Turkey.
authors.forename: Filiz
authors.initials: F
authors.lastname: Hazan
authors.affiliation: Pediatric Neurology Department, Dr. Behcet Uz Children's, Research Hospital, Izmir, Turkey.
authors.forename: Aysel
authors.initials: A
authors.lastname: Ozturk
authors.affiliation: Medical Genetics Department, Duzen Laboratories, Istanbul and Ankara, Turkey.
authors.forename: Kanay
authors.initials: K
authors.lastname: Yararbas
authors.affiliation: Medical Genetics Department, Duzen Laboratories, Istanbul and Ankara, Turkey; Medical Genetics Department, Ankara University Medical School, Ankara, Turkey.
authors.forename: Ajlan
authors.initials: A
authors.lastname: Tukun
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D005220:Fathers; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009035:Mothers; D018482:Muscle, Skeletal / Q000473:pathology; D020125:Mutation, Missense; D058088:Sarcoglycanopathies / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D049031:Sarcoglycans / Q000172:deficiency* / Q000235:genetics*; D035781:Siblings; D014421:Turkey
chemical_list: C526571:SGCA protein, human; C526573:SGCG protein, human; D049031:Sarcoglycans
keywords: LGMD type 2D; adhalin gene; alpha sarcoglycan; novel mutation