HLRCC results from pathogenic variants in the FH gene on chromosome 1. ClinGen has classified the association between FH and HLRCC as DEFINITIVE, indicating the highest level of evidence for gene-disease causality. The FH gene encodes fumarate hydratase, a metabolic enzyme whose inactivation is proposed to drive tumorigenesis through metabolic reprogramming. HLRCC is inherited in an autosomal dominant pattern: one copy of the altered gene in either parent confers a 50% probability that each child will inherit the variant and thereby carry susceptibility to disease manifestations. According to GeneReviews, penetrance for this syndrome is currently unknown and continues to be refined as more population-based testing occurs. GeneReviews further documents emerging genotype-phenotype correlations, noting that certain specific FH variants appear associated with an elevated risk for pheochromocytoma and paraganglioma, highlighting the phenotypic variability that can occur even within the known genetic framework of this syndrome.

According to GeneReviews, prospectively validated clinical diagnostic criteria for HLRCC have not been established. Molecular genetic testing to identify a pathogenic FH variant constitutes the documented approach for definitive diagnosis. GeneReviews describes a range of clinical features that prompt investigation, including the presence of cutaneous leiomyomata, early-onset or multiple uterine fibroids, or renal tumors with characteristic histologic features. Histologic examination of cutaneous lesions typically reveals features consistent with leiomyoma and is considered highly suggestive when multiple lesions are present. Somatic mosaicism has been reported in this condition per GeneReviews. Consensus workshop reports have addressed pediatric surveillance considerations for children with FH tumor predisposition syndrome, as noted by GeneReviews.

No specifically approved treatments for HLRCC as a syndrome are identified in this knowledge packet. Management is organized around individual manifestations, as described in GeneReviews clinical documentation. For cutaneous leiomyomas, dermatologic evaluation is the documented starting point; GeneReviews describes procedural interventions for symptomatic or solitary lesions, along with adjunctive medications targeting vasodilation and neuropathic pain mechanisms for lesions associated with chronic pain, though lesions carry a high rate of recurrence. For uterine fibroids, GeneReviews documents that females with FH tumor predisposition syndrome characteristically require earlier gynecologic intervention than individuals in the general population, with both medical management options and surgical approaches described. For renal tumors, GeneReviews emphasizes the aggressive nature of FH-related renal cell carcinoma and documents that early detection and surgical excision are regarded as critical given the tumor's propensity for early metastasis; GeneReviews notes that specialized expertise in the management of this tumor type is an important aspect of care. Targeted combination approaches for FH-related renal cell carcinoma involving tumor vasculature and metabolic mechanisms are under investigation in clinical trials, as documented in GeneReviews.

The prognosis in HLRCC is variable and depends substantially on the specific manifestations present and whether renal cell carcinoma develops. Cutaneous leiomyomas are benign and do not directly affect survival but can cause significant chronic pain and cosmetic impact. Uterine leiomyomata, while benign, often require intervention and can affect quality of life and reproductive outcomes. According to GeneReviews, renal tumors associated with FH tumor predisposition syndrome are characterized as highly aggressive with early metastatic potential, making the development of renal cell carcinoma the primary determinant of long-term outcomes in affected individuals. GeneReviews notes that penetrance is currently unknown and phenotypic variability is substantial, meaning many individuals carrying FH pathogenic variants may experience only a subset of manifestations or may go unrecognized. As population-based testing expands, GeneReviews anticipates that a wider spectrum of phenotypic variability will become apparent.

Several active clinical trial records are certified for HLRCC on ClinicalTrials.gov. Notable active studies include a Phase 2 trial (NCT04981509), sponsored by the National Cancer Institute, evaluating a combination of targeted and immunotherapy agents for advanced kidney cancer including FH-related renal cell carcinoma, with enrollment active through 2027. A Phase 1 study (NCT07716735) targeting metabolic pathways in HLRCC-related tumors is planned at an academic cancer center. Additional active studies include investigations of kidney and urothelial tumor metabolism (NCT04623502) and a natural history study (NCT03749980) with extended follow-up through 2028. GeneReviews documents ongoing investigation of approaches that target tumor vasculature and metabolic vulnerabilities specific to FH-deficient tumors, with prior combination-regimen studies reporting objective responses in this population. The broader research landscape for HLRCC encompasses case reports, biomarker research, gene therapy-related publications, and reviews, reflecting active scientific engagement with this hereditary cancer syndrome. Active clinical trials for this condition are listed on ClinicalTrials.gov.