However, it is easily misdiagnosed as congenital idiopathic nystagmus in some Chinese patients with OA1 caused by the G-protein coupled receptor 143 (GPR143) gene mutations.
This study was undertaken to analyse the OA1 gene (GPR143) and its involvement in a Spanish family presenting with nystagmus, a common symptom of X-linked ocular albinism (XLOA).
Variants in RARS1 impair ArgRS activity and do not only lead to a classic hypomyelination presentation with nystagmus and spasticity, but to a wide spectrum, ranging from severe, early-onset epileptic encephalopathy with brain atrophy to mild disease with relatively preserved myelination.
Patients with RPGRIP1 mutations have a degeneration of both rod and cone photoreceptors, and, early in life, they experience a severe loss of central acuity, which leads to nystagmus.
Beside the growing number of descriptions of novel CACNA1A mutations with episodic ataxia type 2 phenotype; there are only rare reports on interictal oculomotor signs other than nystagmus.
In over 50% of cases the causative gene is CACNA1A (FHM1), which in some cases produces a phenotype with cerebellar signs, including ataxia and nystagmus.
CACNA1A loss-of-function mutations classically present as episodic ataxia type 2 (EA2), with brief episodes of ataxia and nystagmus, or with progressive spinocerebellar ataxia (SCA6).
Although clinical features associated with the T666MCACNA1A mutation are highly variable, downbeat positioning nystagmus may be an important clinical feature of this disease.
The common manifestations of the disease in patients with PLP1 mutations or duplications in this study were nystagmus in early infancy, dysmyelination revealed by magnetic resonance imaging (MRI), and auditory brain response abnormalities.
Pelizaeus-Merzbacher disease (PMD; MIM#312080) is a rare X-linked leukodystrophy presenting with motor developmental delay associated with spasticity and nystagmus.
A patient who developed nystagmus at 16 months and progressive spastic ataxia at 18 months was found to have a 19-base pair (bp) deletion of a G-rich region near the 5' end of intron 3 of the PLP gene.
Based on eight novel patients and all CASK-mutation positive males reported previously three phenotypic groups can be distinguished that represent a clinical continuum: (i) MICPCH with severe epileptic encephalopathy caused by hemizygous loss-of-function mutations, (ii) MICPCH associated with inactivating alterations in the mosaic state or a partly penetrant mutation, and (iii) syndromic/nonsyndromic mild to severe ID with or without nystagmus caused by CASK missense and splice mutations that leave the CASK protein intact but likely alter its function or reduce the amount of normal protein.
To scrutinize the etiology of a four-generation Japanese family with autosomal dominant nystagmus associated with anterior and posterior segment anomalies, the PAX6 gene was examined.
Patients with C-terminal CASK mutations also present with nystagmus and, strikingly, we show that these mutations specifically disrupt interaction with FRMD7.