MedGen

Neuronal ceroid lipofuscinosis-11 (CLN11) is an autosomal recessive progressive neurodegenerative disorder characterized by seizures (often refractory), progressive cerebellar ataxia and gait abnormalities, cognitive decline particularly affecting executive function, and behavioral abnormalities. The age at onset is variable, ranging from midchildhood to the second or third decades. Most patients have progressive visual loss with retinal abnormalities and cataracts; visual hallucinations may occur and many patients are photosensitive. The severity of the disorder is variable, but it is progressive and can lead to severe disability with blindness, loss of ambulation, and severe cognitive impairment (Huin et al., 2020; Neuray et al., 2021). For a general phenotypic description and a discussion of genetic heterogeneity of CLN, see CLN1 (256730). [from OMIM]

The spectrum of GRN frontotemporal dementia (GRN-FTD) includes the behavioral variant (bvFTD), primary progressive aphasia (PPA; further subcategorized as progressive nonfluent aphasia [PNFA] and semantic dementia [SD]), and movement disorders with extrapyramidal features such as parkinsonism and corticobasal syndrome (CBS). A broad range of clinical features both within and between families is observed. The age of onset ranges from 35 to 87 years. Behavioral disturbances are the most common early feature, followed by progressive aphasia. Impairment in executive function manifests as loss of judgment and insight. In early stages, PPA often manifests as deficits in naming, word finding, or word comprehension. In late stages, affected individuals often become mute and lose their ability to communicate. Early findings of parkinsonism include rigidity, bradykinesia or akinesia (slowing or absence of movements), limb dystonia, apraxia (loss of ability to carry out learned purposeful movements), and disequilibrium. Late motor findings may include myoclonus, dysarthria, and dysphagia. Most affected individuals eventually lose the ability to walk. Disease duration is three to 12 years. [from GeneReviews]