Lanceolate hair-J (lah(J)): A mouse model for human hair disorders

Lanceolate hair-J (lah(J)) arose spontaneously in 1994 on the DBA/1LacJ inb red background at The Jackson Laboratory. Mutant mice were runted, alopecic , and lacked vibrissae. As they aged, their skin wrinkled. Affected mice de veloped a noninflammatory, proliferative skin disease with follicular dystr ophy. Hair fibers developed a number of abnormalities including periodic no dules along the shaft (trichorrhexis nodosa), compaction resembling trichor rhexis invaginata, spiral fractures, broken tips, and lance-shaped tips. Th is mutation exhibits some characteristics that resemble an autosomal recess ive ichthyosiform disease that occurs in humans characterized in part by pe culiar, invaginating, multinodal, hair shaft abnormalities known as Nethert on's syndrome. Periodic nodules also resemble the human genetic based disea se monilethrix. This autosomal recessive mouse mutation, allelic with lance olate hair (lah), based on breeding studies, is located on mouse Chromosome 18, within a cluster of genes coding for adhesion molecules. Homozygotes f or either of these allelic mouse mutations have elevated serum IgE levels, a feature also common with human Netherton's syndrome.