The most prominent symptoms initially observed in<unk>  are ocular (affect the eye). Initial characteristics are usually identified at birth or in early infancy, with parents often noticing abnormal eye features or that their child fails to show a response to light. The first visible finding is leukocoria, a grayish-yellow pupillary reflection that originates from a mass of disorganized tissue behind the lens. This material, which possibly includes an already detached retina, may be confused with a tumor and thus is termed pseudoglioma. However, an affected baby may have a normally sized eye globe and unremarkable iris, anterior chamber, cornea and intraocular pressure. Over the first few months of life, complete or partial retinal detachment evolves. From infancy through childhood, the patient may undergo progressive changes in the disease. Disease progression often includes vitreoretinal hemorrhages, the formation of cataracts, deterioration of the iris with adhesions forming between the iris and the lens or the cornea, and shallowing of the anterior chamber which may increase intraocular pressure, causing eye pain. As the situation worsens, there is corneal opacification, where the cornea becomes opaque, and band keratopathy. Intraocular pressure is lost and the globe shrinks. In the last stage of<unk> , the globes appear small and sunken in (phthisis bulbi) and the cornea appears to be milky. Auditory symptoms (affect the ear) are common with<unk> . Progressive hearing loss has been reported to occur in 85–90% of patients and onset is generally in childhood and before the patient reaches their mid-20s. Early hearing loss is sensorineural (caused by damage to the inner ear or auditory nerve), mild and asymmetric. By adolescence, high-frequency hearing loss begins to appear. Hearing loss is severe, symmetric, and broad-spectrum by the age of 35 years. However, studies show that while hearing deteriorates, the ability to speak well is highly preserved. The slowly progressing hearing loss is more problematic to adjust to than the congenital blindness for most people with<unk> . Additional characteristics Individuals with<unk>  can also have cognitive and behavioral symptoms. Developmental delay or learning difficulties are present in about 30 to 50% of males who have<unk> . Psycho-social disturbances and poorly characterized behavior abnormalities may also be present. In a study reporting extraocular manifestations in 56 patients with<unk> , conditions reported included cognitive impairment (28% of patients), behavioral issues, for example autism spectrum disorder (27% of patients presented with autism or autism-like disorders), neurological features, including seizure disorders and epilepsy (16% of patients reported seizures or seizure history), and peripheral vascular disease (38% of patients). Additionally, children with visual impairment have been shown to struggle establishing regular sleep/wake cycles due to reduced light perception impacting on their understanding of night and day; this can impact on the individual’s behavior, mood and cognitive ability. Consistent with this, some case reports of<unk>  patients have reported the presence of sleep disorders. Peripheral vascular disease (PVD) has also been associated with<unk> . In a study of 56 patients with<unk> , 21 patients (38%) reported PVD (including varicose veins, peripheral venous stasis ulcers and erectile dysfunction). Due to the known role of the protein<unk>  in the vascular development of the eye and inner ear, as well as the association with PVD,<unk>  is thought to have an important angiogenic role in the body.
Norrie disease
Waldmann disease
Karak syndrome
Camisa disease
Batten disease
Leber congenital amaurosis
Gleich's syndrome
Zaki syndrome