A Frameshift Mutation within LAMC2 Is Responsible for Herlitz Type Junctional Epidermolysis Bullosa (HJEB) in Black Headed Mutton Sheep

Junctional epidermolysis bullosa (JEB) is a hereditary mechanobullous skin disease in humans and animals. A Herlitz type JEB was identified in German Black Headed Mutton (BHM) sheep and affected lambs were reproduced in a breeding trial. Affected lambs showed skin and mucous membranes blistering and all affected lambs died within the first weeks of life. The pedigree data were consistent with a monogenic autosomal recessive inheritance. Immunofluorescence showed a reduced expression of laminin 5 protein which consists of 3 subunits encoded by the genes LAMA3, LAMB3 and LAMC2. We screened these genes for polymorphisms. Linkage and genome-wide association analyses identified LAMC2 as the most likely candidate for HJEB. A two base pair deletion within exon 18 of the LAMC2 gene (FM872310:c.2746delCA) causes a frameshift mutation resulting in a premature stop codon (p.A928*) 13 triplets downstream of this mutation and in addition, introduces an alternative splicing of exon 18 LAMC2. This deletion showed a perfect co-segregation with HJEB in all 740 analysed BHM sheep. Identification of the LAMC2 deletion means an animal model for HJEB is now available to develop therapeutic approaches of relevance to the human form of this disease

Transcription Factor Binding Site Polymorphism in the Motilin Gene Associated with Left-Sided Displacement of the Abomasum in German Holstein Cattle

Left-sided displacement of the abomasum (LDA) is a common disease in many dairy cattle breeds. A genome-wide screen for QTL for LDA in German Holstein (GH) cows indicated motilin (MLN) as a candidate gene on bovine chromosome 23. Genomic DNA sequence analysis of MLN revealed a total of 32 polymorphisms. All informative polymorphisms used for association analyses in a random sample of 1,136 GH cows confirmed MLN as a candidate for LDA. A single nucleotide polymorphism (FN298674:g.90T>C) located within the first non-coding exon of bovine MLN affects a NKX2-5 transcription factor binding site and showed significant associations (ORallele = 0.64; −log10Pallele = 6.8, −log10Pgenotype = 7.0) with LDA. An expression study gave evidence of a significantly decreased MLN expression in cows carrying the mutant allele (C). In individuals heterozygous or homozygous for the mutation, MLN expression was decreased by 89% relative to the wildtype. FN298674:g.90T>C may therefore play a role in bovine LDA via the motility of the abomasum. This MLN SNP appears useful to reduce the incidence of LDA in German Holstein cattle and provides a first step towards a deeper understanding of the genetics of LDA

A MITF Mutation Associated with a Dominant White Phenotype and Bilateral Deafness in German Fleckvieh Cattle

A dominantly inherited syndrome associated with hypopigmentation, heterochromia irides, colobomatous eyes and bilateral hearing loss has been ascertained in Fleckvieh cattle (German White Fleckvieh syndrome). This syndrome has been mapped to bovine chromosome (BTA) 22 using a genome-wide association study with the bovine high density single nucleotide polymorphism array. An R210I missense mutation has been identified within microphthalmia-associated transcription factor (MITF) as responsible for this syndrome. The mutation is located in the highly conserved basic region of the protein and causes a negative-dominant effect. SOX10 and PAX3 promoter binding site mutations in MITF could be ruled out as causative for the German White Fleckvieh syndrome. Molecular characterization of this newly detected bovine syndrome means a large animal model is now available for the Tietz syndrome in humans

Least-squares means (LSM) with their corresponding standard errors (SE) of the frequency of LDA on the underlying logit scale for the genotypes of the SNPs FN298674:g.90T>C and FN298674:g.1891insG and the contrasts among the LSMs with their test statistics and P-values.

<p>Genotypic means for the frequency of LDA were estimated through LSMs in a mixed logit model correcting for data stratification.</p

Results of the expression analysis for FN298674:g.90T>C within <i>motilin</i> (<i>MLN</i>).

<p>The mean relative expression levels of <i>MLN</i> with their standard errors are given for the wildtype genotype T/T, the heterozygously (C/T) and the homozygously mutated genotype (C/C) standardized on the mean of the genotype T/T. Furthermore, the F-values and P-values for the differences in mean relative expression levels among the genotype T/T versus the genotypes C/T and C/C as well C/T versus C/C are given. <i>RPL4</i> was used as housekeeping gene.</p

All identified polymorphisms with their location within <i>motilin</i> (<i>MLN</i>).

*<p>IRD labeled.</p><p>Informative (I) polymorphisms are indicated by a plus sign. The primer pairs used are given with their annealing temperatures (AT) and product sizes (PS).</p

Mutation within the bovine <i>motilin (MLN)</i> gene associated with LDA.

<p>Sequence of <i>MLN</i> surrounding the FN298674:g.90T>C SNP for the wildtype (control cow) and the mutated allele (LDA-affected cow) as well as the 3′ end of the predicted <i>MLN</i> promoter, the 5′ start sequence of the non-coding first exon of <i>MLN</i> and the NKX2-5 transcription factor binding site are shown. Furthermore, chromatograms of this section are given for each one of the homozygous wildtype, heterozygous and homozygous mutant individuals.</p

Association study for LDA using SNPs within <i>motilin</i> for 1,136 German Holstein cows.

<p>For each SNP, minor allele frequencies (MAF), the MAF allele, odds ratios (OR) with their 95% confidence intervals (CI), polymorphism information content (PIC), and heterozygosity (HET) are given. Furthermore, −log₁₀P-values (P) are given for genotype (gt), allele, among homozygotes (hom) and for genotype after correcting the data for stratification (strat).</p