Molecular analysis of the human laminin alpha3a chain gene (LAMA3a): a strategy for mutation identification and DNA-based prenatal diagnosis in Herlitz junctional epidermolysis bullosa.
Mutations in the genes (LAMA3, LAMB3, and LAMC2) encoding the subunit polypeptides of the cutaneous basement membrane zone protein laminin 5 have been reported in different forms of junctional epidermolysis bullosa (JEB), an inherited blistering skin disease. In this study, we present the complete exon-intron organization of the "a" transcript of the laminin alpha3 chain gene, LAMA3a, which is expressed primarily in the skin. We have performed fine-resolution mapping of this gene on chromosome 18q11.2 using a human-hamster radiation hybrid panel. We have also developed a mutation-detection strategy based on the exon-intron structure of LAMA3a. This strategy, based on PCR amplification of genomic sequences, followed by heteroduplex scanning and automated nucleotide sequencing, was used for successful mutation screening in a family with the lethal (Herlitz) type of JEB, and two novel LAMA3 mutations were identified in the proband. The mutations consisted of a single-base pair deletion in LAMA3a exon A11 on the paternal allele, designated 1239delC, and a two-base pair deletion in LAMA3a exon A23 on the maternal allele, designated 2959delGG. This information was also used for DNA-based prenatal testing in a subsequent pregnancy in this family. Collectively, these results attest to our expanding capability to elucidate the genetic basis of various forms of epidermolysis bullosa using molecular techniques.
Pulkkinen
L
L
Department of Dermatology and Cutaneous Biology, Jefferson Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
Cserhalmi-Friedman
P B
PB
Tang
M
M
Ryan
M C
MC
Uitto
J
J
Christiano
A M
AM
D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D006224:Cricetinae; D004247:DNA / Q000235:genetics*; D004252:DNA Mutational Analysis; D016109:Epidermolysis Bullosa, Junctional / Q000175:diagnosis* / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005260:Female; D006801:Humans; D007223:Infant; D007438:Introns / Q000235:genetics; D007797:Laminin / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D009692:Nucleic Acid Heteroduplexes / Q000235:genetics; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*
D007797:Laminin; D009692:Nucleic Acid Heteroduplexes; C095567:laminin alpha 3; D004247:DNA