Circulating levels of both hormones are an important factor in weight control. While often associated with obesity, both hormones and their respective effects have been implicated in the pathophysiology of anorexia nervosa and bulimia nervosa. Leptin can also be used to distinguish between constitutional thinness found in a healthy person with a low BMI and an individual with anorexia nervosa. Gut bacteria and immune system: studies have shown that a majority of patients with anorexia and bulimia nervosa have elevated levels of autoantibodies that affect hormones and neuropeptides that regulate appetite control and the stress response. There may be a direct correlation between autoantibody levels and associated psychological traits. Later study revealed that autoantibodies reactive with alpha-MSH are, in fact, generated against ClpB, a protein produced by certain gut bacteria e.g. Escherichia coli. ClpB protein was identified as a conformational antigen-mimetic of alpha-MSH. In patients with eating disorders plasma levels of anti-ClpB IgG and IgM correalated with patients psychological traits
Infection: PANDAS is an abbreviation for the controversial Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections hypothesis. Children with PANDAS are postulated to "have obsessive-compulsive disorder (OCD) and/or tic disorders such as Tourette syndrome, and in whom symptoms worsen following infections such as strep throat". (NIMH) PANDAS and the broader PANS are hypothesized to be a precipitating factor in the development of anorexia nervosa in some cases, (PANDAS AN). Lesions: studies have shown that lesions to the right frontal lobe or temporal lobe can cause the pathological symptoms of an eating disorder.
Opsismodysplasia is a type of skeletal dysplasia (a bone disease that interferes with bone development) first described by Zonana and associates in 1977, and designated under its current name by Maroteaux (1984). Derived from the Greek opsismos ("late"), the name "opsismodysplasia" describes a delay in bone maturation. In addition to this delay, the disorder is characterized by micromelia (short or undersized bones), particularly of the hands and feet, delay of ossification (bone cell formation), platyspondyly (flattened vertebrae), irregular metaphyses, an array of facial aberrations and respiratory distress related to chronic infection. Opsismodysplasia is congenital, being apparent at birth. It has a variable mortality, with some affected individuals living to adulthood. The disorder is rare, with an incidence of less than 1 per 1,000,000 worldwide. It is inherited in an autosomal recessive pattern, which means the defective (mutated) gene that causes the disorder is located on an autosome, and the disorder occurs when two copies of this defective gene are inherited. No specific gene has been found to be associated with the disorder. It is similar to spondylometaphyseal dysplasia, Sedaghatian type. Presentation
Opsismodysplasia can be characterized by a delay in bone maturation, which refers to "bone aging", an expected sequence of developmental changes in the skeleton corresponding to the chronological age of a person. Factors such as gender and ethnicity also play a role in bone age assessment. The only indicator of physical development that can be applied from birth through mature adulthood is bone age.