The packet attributes the condition to variants in the GRN gene, located on chromosome 17, with autosomal dominant inheritance. No ClinGen validity classification is supplied in the packet for GRN.

GeneReviews reports that most (95%) individuals diagnosed with GRN-FTD have an affected parent, and that the proportion of cases caused by a de novo GRN pathogenic variant is unknown but estimated at 5% or fewer. It states that the family history of some individuals may appear negative because of a milder phenotype, early death of a parent, or age-related or reduced penetrance.

Penetrance is described as about 90% by age 75 years, with apparent reduced penetrance also observed on occasion; for the common pathogenic variant, 60% of individuals were affected by age 60 years and more than 95% by age 70 years. GeneReviews states that no obvious correlations between age of onset, disease duration, or clinical phenotype and specific GRN pathogenic variants have been identified, and that clinical variability is high among individuals with the same variant.

GeneReviews describes GRN-FTD as suspected on the basis of clinical presentations and neuroimaging findings, and states that presentations vary widely within and among families and may resemble behavioral variant FTD, primary progressive aphasia, atypical parkinsonism, or corticobasal syndrome.

For behavioral variant FTD, listed features include early disinhibition, apathy or inertia, loss of sympathy or empathy, perseverative or compulsive behavior, and hyperorality with dietary changes, with executive deficits and relative sparing of episodic memory and visuospatial skills. For primary progressive aphasia, the criteria describe language difficulty as the most prominent feature and principal cause of impaired daily living. The nonfluent variant requires at least one core feature (agrammatism, or effortful, halting speech with speech sound errors) and at least two of three supportive features; the semantic variant requires impaired confrontation naming and single-word comprehension plus at least three of four additional features. GeneReviews notes that the logopenic variant has not been associated with GRN-FTD to date.

The differential diagnosis in GeneReviews includes neuroimaging-detectable mimics such as white matter diseases, frontal lobe tumors, and cerebrovascular disease, and clinical overlap with Parkinson disease, Alzheimer disease, Pick disease, corticobasal degeneration, progressive supranuclear palsy, and Creutzfeldt-Jakob disease. GeneReviews states that this overlap makes it difficult to predict from clinical presentation alone which family has a GRN pathogenic variant.

Evaluations after diagnosis listed in GeneReviews include detailed general, neurologic, and family history, physical and neurologic examination, and cognitive examination, with neuropsychological assessment described as more comprehensive when bedside assessments are not informative enough.

The packet does not include certified FDA-approved treatment records for this condition, so approved options are not established in this packet. GeneReviews states that there is currently no known treatment for GRN-FTD or FTD in general and that there is no consensus treatment guideline for GRN-FTD.

GeneReviews describes psychosocial support, including occupational therapy and environmental and physical interventions, as essential in the management of FTD, and describes psychological support and support groups for caregivers as valuable given the considerable caregiver burden. It states that behavioral and psychological manifestations are treated as in other types of FTD: apathy, impulsivity, and compulsiveness may respond to selective serotonin reuptake inhibitors, and roaming, delusions, and hallucinations may respond to antipsychotic medications. Donepezil is described as associated with exacerbation of disinhibition and compulsion symptoms.

GeneReviews states that randomized-trial evidence is limited and that the findings it summarizes for FTD in general require confirmation in larger trials; these include reports on trazodone, paroxetine, galantamine, rivastigmine, methylphenidate, dextroamphetamine, and memantine, with mixed benefits and some worsening of cognitive measures. It further states that patients are often followed in a memory disorder clinic or similar multidisciplinary clinic involving neurologic and psychiatric services.

The packet does not include a dedicated prognosis source; the natural-history details here come from GeneReviews. Onset is reported between 35 and 87 years, with a mean of 64.9 years. In a study cited by GeneReviews, median age at death was 65.5 years in individuals with a GRN pathogenic variant versus 69.0 years in those without one. GeneReviews states that most affected individuals eventually lose the ability to walk. Survival figures and outcome expectations beyond these statements are not certified in this packet.

The packet lists 54 active ClinicalTrials.gov records retrieved by a search on the condition name, and its intervention summary indicates that gene therapy trials are among them. Active clinical trials for this condition are listed on ClinicalTrials.gov. Because the search is by condition name, some records are broader than GRN-FTD.

Records that name GRN-related disease include NCT06064890, a Phase 1 study of AVB-101, a gene therapy product, in FTD-GRN, sponsored by AviadoBio Ltd, recruiting, from 2023-08-30 to 2030-03-21; and NCT04408625, a Phase 1/2 study of LY3884963 in frontotemporal dementia with progranulin mutations, sponsored by Prevail Therapeutics, active not recruiting, from 2020-11-09 to 2029-11-30. NCT06066710 is an early Phase 1 study of propranolol in primary progressive aphasia sponsored by the University of Missouri-Columbia, recruiting.

The packet's research digest classifies 371 publications, with Basic Science / Preclinical as the dominant type.