Freckles are not a skin disorder, but people with freckles generally have a lower concentration of photo-protective melanin, and are therefore more susceptible to the harmful effects of UV radiation. It is suggested that people whose skin tends to freckle should avoid overexposure to sun and use sunscreen. Genetics
The presence of freckles is related to rare alleles of the MC1R gene, though it does not differentiate whether an individual will have freckles if they have one or even two copies of this gene. Also, individuals with no copies of the MC1R do sometimes display freckles. Even so, individuals with a high number of freckling sites have one or more of variants of the MC1R gene. Of the variants of the MC1R gene Arg151Cys, Arg160Trp, and Asp294His are the most common in the freckled subjects. The MC1R gene is also associated with red hair more strongly than with freckles. Most red-haired individuals have two variants of the MC1R gene and almost all have one. The variants that cause red hair are the same that cause freckling. Freckling can also be found in areas, such as Japan, where red hair is not seen. These individuals have the variant Val92Met which is also found in Europeans, although it has minimal effects on their pigmentation. The R162Q allele has a disputed involvement in freckling.The variants of the MC1R gene that are linked with freckles started to emerge in the human genotype when humans started to leave Africa.
Studies have estimated the prevalence of BSS in people affected by Parkinsons to be between 3% and 18%. Gene mutations
Several gene mutations have been identified in patients with camptocormia. These include the RYR1 gene in axial myopathy, the DMPK gene in myotonic dystrophy, and genes related to dysferlinopathy and Parkinsons disease. These genes could serve as targets for gene therapy to treat the condition in the years to come. Diagnosis
In order to qualify a patients condition as BSS, the bending angle must be greater than 45 degrees. While the presence of the condition is very easy to note, the cause of the condition is much more difficult to discern. Conditions not considered to be BSS include vertebral fractures, previously existing conditions, and ankylosing spondylitis. Lower-back CT scans and MRIs can typically be used to visualize the cause of the disease. Further identification of the cause can be done by histochemical or cellular analysis of muscle biopsy. Camptocormia is becoming progressively found in patients with Parkinsons disease. The diagnosis of Parkinsons-associated camptocormia includes the use of imaging of the brain and the spinal cord, along with electromyography or muscle biopsies. Muscle biopsies are also a useful tool to diagnose camptocormia. Muscle biopsies found to have variable muscle fiber sizes and even endomysial fibrosis may be markers of bent spine syndrome. In addition, disorganized internal architecture and little necrosis or regeneration is a marker of camptocormia. Patients with camptocormia present with reduced strength and stooped posture when standing due to weakened paraspinous muscles (muscles parallel to the spine).