Patient's question:
Photophobia, nystagmus at 3 years old, scared by poultryDoctor's answer:
Disease Analysis: Congenital nystagmus is a disease characterized by persistent horizontal, pendular nystagmus, with no specific abnormalities in the eyes themselves.Guidance: The exact pathogenesis remains unclear, but it has a strong genetic component. Both autosomal dominant and recessive inheritance patterns have been reported, with autosomal dominant inheritance being more common. Multiple family members may be affected, with horizontal, pendular nystagmus present from an early age. The amplitude increases during lateral gaze, and varying degrees of vision impairment associated with nystagmus may occur. In this family pedigree, 7 cases of nystagmus appeared from the first to the fourth generation, with transmission across generations. Male patients pass the condition to their daughters (sons are unaffected), while female patients pass it to half of their sons and daughters. Therefore, female patients are more common than male patients. There is no history of consanguineous marriage in this family. All patients exhibit horizontal, pendular nystagmus with increased amplitude during lateral gaze. Their nystagmus frequencies vary, and they have varying degrees of vision impairment, color vision abnormalities, and normal extraocular, fundoscopic, and systemic examinations.
Lifestyle Care: Based on the family pedigree characteristics, which align with autosomal dominant inheritance, the diagnosis of familial congenital nystagmus is established. Since this condition does not show significant changes throughout life, there is currently no specific clinical treatment. The treatment principles include: ① Corrective lenses for refractive errors; ② Prisms for patients with strabismus and head/neck tilt; ③ Surgery to weaken the extraocular muscles, reducing the severity of nystagmus.
Human pendular nystagmus is controlled by a dominant gene on the X chromosome, while galactosemia is controlled by a recessive gene on the autosomes. A female with pendular nystagmus marries a normal male and has a son with galactosemia (normal eyes). The probability of their second child being a boy with both conditions is 1/8.