Mechanical laminitis can occur when a horse habitually paws, is ridden or driven on hard surfaces ("road founder"), or in cases of excessive weight-bearing due to compensation for the opposing limb, a process called support limb laminitis. Support limb laminitis is most common in horses suffering from severe injury to one limb, such as fracture, resulting in a non-weight bearing state that forces them to take excessive load on the opposing limb. This causes decreased blood flow to the cells, decreasing oxygen and nutrient delivery, and thus altering their metabolism which results in laminitis. Theories of pathophysiology
Matrix metalloproteinasesOne of the newest theories for the molecular basis of laminitis involves matrix metalloproteinases (MMPs). Metalloproteinases are enzymes that can degrade collagen, growth factors, and cytokines to remodel the extracellular matrix of tissues. To prevent tissue damage, they are regulated by tissue inhibitors of metalloproteinases (TIMPs). In cases of laminitis, an underlying cause is thought to cause an imbalance of MMPs and TIMPs, favoring MMPs, so that they may cleave substances within the extracellular matrix and therefore break down the basement membrane. Since the basement membrane is the main link between the hoof wall and the connective tissue of P3, it is thought that its destruction results in their separation. MMP-2 and MMP-9 are the primary enzymes thought to be linked to laminitis. Theories for developmentThere are multiple theories as to how laminitis develops.
Otofaciocervical syndrome, also known as Fara Chlupackova syndrome, are a small group of rare developmental disorders of genetic origin which are characterized by facial dysmorphisms, long neck, preauricular and/or branchial pits, cervical muscle hypoplasia, hearing loss, and mild intellectual disabilities. Additional findings include vertebral anomalies and short stature. Types
There are two types of OFC:

Otofaciocervical syndrome type 1
It is characterized by facial dysmorphisms, low-set cup-shaped ears, preauricular sinus or cyst, hearing loss, branchial and skeletal anomalies, low-set clavicle bones, winged scapulae, sloping shoulders and mild intellectual disabilities. It is caused by autosomal dominant mutations in the EYA1 gene in chromosome 8. Only 11 cases have been reported in medical literature. Otofaciocervical syndrome type 2
It is characterized by the same symptoms in type 1, this disorder is different from type 1 because of its genetic cause and because of its additional features: thymus development alterations with T-cell immunodeficiency and recurrent infections which may turn fatal. It is caused by autosomal recessive mutations in the PAX1 gene in chromosome 20. Only 13 cases have been described in medical literature. == References ==