Epidermolysis Bullosa with Muscular Dystrophy (EB-MD)
Approximately 50 cases of epidermolysis bullosa-muscular dystrophy (EB-MD) have been reported worldwide. Blistering occurs early and is generally mild. Muscular dystrophy may not appear until later childhood, adolescence, or in some cases adulthood, and can cause immobility and eventually death later in life. Mutations have been described throughout the PLEC (also known as PLEC1) gene (8q24). Inheritance is autosomal recessive.
Epodermolysis Bullosa with Pyloric Atresia (EB-PA)
Epidermolysis bullosa with pyloric atresia (EB-PA) is characterized by fragility of the skin and mucous membranes, manifest by blistering with little or no trauma; congenital pyloric atresia; and ureteral and renal anomalies (dysplastic/multicystic kidney, hydronephrosis/hydroureter, ureterocele, duplicated renal collecting system, absent bladder). The course of EB-PA is usually severe and often lethal in the neonatal period. Although most affected children succumb as neonates, those who survive may have severe blistering with formation of granulation tissue on the skin around the mouth, nose, fingers, and toes, and internally around the trachea. However, some affected individuals have little or no blistering later in life. Additional features shared by EB-PA and the other major forms of EB include congenital localized absence of skin (aplasia cutis congenita), milia, nail dystrophy, scarring alopecia, hypotrichosis, and contractures.
Because the clinical features of all types of epidermolysis bullosa (EB) overlap significantly, examination of a skin biopsy by transmission electron microscopy (TEM) and/ or immunofluorescent antibody/antigen mapping is usually required to establish the diagnosis. The three genes known to be associated with EB-PA are ITGB4 (~80% of EB-PA), ITGA6 (~5%), and PLEC (~15%).
EB-PA is inherited in an autosomal recessive manner.
Epidermolysis Bullosa Simplex, Ogna Type
Epidermolysis bullosa simplex, Ogna type has been observed in one Norwegian and one German family with autosomal dominant inheritance. It is a result of the site-specific missense p.Arg2110Trp mutation in PLEC. A single lethal case of autosomal recessive EBS resulting from PLEC mutations has also been described, as has a case of EBS with severe mucous membrane involvement as a result of mutations in PLEC.
- GeneReviews: Epidermolysis Bullosa with Pyloric Atresia
- OMIM #612138: Epidermolysis Bullosa Simplex with Pyloric Atresia
- OMIM #226670: Epidermolysis Bullosa Simplex with Muscular Dystrophy
- OMIM #131950: Epidermolysis Bullosa Simplex, Ogna Type
This test is indicated for:
- Confirmation of a clinical diagnosis of PLEC-related epidermolysis bullosa in individuals who have tested negative for sequence analysis
- Carrier testing in adults with a family history of PLEC-related epidermolysis bullosa who have tested negative for sequence analysis
Detection is limited to duplications and deletions. The CGH array will not detect point or intronic mutations. Results of molecular analysis must be interpreted in the context of the patient's clinical and/or biochemical phenotype.
Isolation using the Perkin Elmer™Chemagen™ Chemagen™ Automated Extraction method or Qiagen™ Puregene kit for DNA extraction is recommended.
Infants and Young Children (<2 years of age): 2-3 ml
Children > 2 years of age to 10 years old: 3-5 ml
Older Children & Adults: 5-10 ml
Autopsy: 2-3 ml unclotted cord or cardiac blood
Submit copies of diagnostic biochemical test results with the sample, if appropriate. Contact the laboratory if further information is needed.
Sequence analysis is required before deletion/duplication analysis by targeted CGH array. If sequencing is performed outside of EGL Genetics, please submit a copy of the sequencing report with the test requisition.
- Sequence analysis of the PLEC gene is available and is required before deletion/duplication analysis.
- Custom diagnostic mutation analysis (KM) is available to family members if mutations are identified by targeted mutation testing or sequencing analysis.
- Prenatal testing is available to adults who are confirmed carriers of mutations. Please contact the laboratory genetic counselor to discuss appropriate testing prior to collecting a prenatal specimen.