Genetic Causes
According to researchers, there is a belief that certain cases of Horner’s syndrome can be inherited, potentially as a consequence of an autosomal dominant trait. This implies that the disorder may develop with only one copy of the abnormal gene. It can be passed on to a child by either parent or may occur due to an unexpected genetic mutation. If Horner’s syndrome develops before the age of two, the affected individual may have irises of different colors or the affected iris may have reduced pigmentation.
Differential Diagnosis
There are various factors that can contribute to the development of Horner’s syndrome, in addition to those mentioned. Any form of trauma or damage to the sympathetic nerve fibers that extend from the hypothalamus through the neck and chest and up to the eyes can lead to this condition. When the pupils are of different sizes, it is referred to as anisocoria, which can be benign but may also indicate an underlying serious condition. Damage to the oculomotor nerve, responsible for lifting the eyelid, can cause drooping eyelids. This type of ptosis typically results in more pronounced effects. Additionally, ptosis in one eyelid can also be caused by myasthenia gravis, a condition that causes generalized muscle weakness.