RVCL-S
Introduction
Retinal vasculopathy with cerebral leukodystrophy and systemic manifestations (RVCL-S) is a rare, autosomal dominant multisystem disorder characterized by a progressive small-vessel vasculopathy. The disease primarily affects the retina and central nervous system but also involves several internal organs, leading to a broad and heterogeneous clinical presentation. Typically manifesting in mid-adulthood, RVCL-S is associated with substantial morbidity and reduced life expectancy. Owing to its variable presentation and the presence of tumor-like brain lesions, it is frequently misdiagnosed as an inflammatory, demyelinating, or neoplastic condition.
Genetics
RVCL-S is caused by heterozygous frameshift mutations in the C-terminal region of the TREX1 gene located on chromosome 3. These mutations result in truncation of the protein and loss of its normal C-terminal domain, which is essential for proper intracellular localization. The disorder follows an autosomal dominant inheritance pattern with high penetrance, and affected individuals often have a clear family history of similar symptoms.
Unlike other disorders associated with TREX1 mutations, such as Aicardi–Goutières syndrome, the mutations in RVCL-S do not primarily impair exonuclease activity but instead lead to mislocalization of the protein within the cell, which is central to disease pathogenesis.
Pathophysiology
The pathophysiology of RVCL-S is characterized by a non-inflammatory obliterative microangiopathy. The mutant TREX1 protein accumulates abnormally within cells, particularly in endothelial cells, leading to dysfunction and progressive vascular damage. This results in thickening of vessel walls, luminal narrowing, and eventual occlusion of small vessels. Histopathological examination typically reveals hyalinization, fibrosis, and capillary loss with minimal or absent inflammatory infiltrates, distinguishing the condition from primary vasculitides. The resulting chronic ischemia predominantly affects highly vascularized tissues such as the retina and cerebral white matter, leading to the characteristic clinical and radiological features.
Epidemiology
It is a very rare disorder, with only a limited number of families reported worldwide. Its true prevalence is unknown and likely underestimated due to frequent misdiagnosis. The disease typically presents between the ages of 35 and 50, although there is variability. Both males and females are equally affected. Because of its autosomal dominant inheritance pattern, the disease often occurs in multiple members across successive generations within affected families.
Clinical Manifestations
The clinical manifestations of RVCL-S are multisystemic and progressive, reflecting widespread small-vessel involvement. Ophthalmologic symptoms are often the earliest feature and include a progressive retinopathy characterized by telangiectasias, microaneurysms, capillary non-perfusion, and macular edema, eventually leading to visual impairment and possible blindness. Neurological involvement is prominent and includes migraine-like headaches, focal neurological deficits, and progressive cognitive decline that may culminate in subcortical dementia; seizures can also occur but are less common.
Neuroimaging typically demonstrates multifocal white matter lesions, often with contrast enhancement and occasionally with a pseudotumoral appearance, which may lead to diagnostic confusion. In addition to ocular and neurological features, systemic involvement is common and may include renal dysfunction with proteinuria, hepatic abnormalities, such as elevated transaminases and nodular regenerative hyperplasia, gastrointestinal complications, including bleeding or ischemia, and hematological findings, such as anemia.
Diagnosis
The diagnosis of RVCL-S is based on integrating clinical, radiological, and genetic findings. A detailed family history may reveal an autosomal dominant pattern of similar symptoms. Characteristic features include the combination of retinal vasculopathy, cerebral white matter disease, and evidence of systemic involvement. Magnetic resonance imaging of the brain typically shows multifocal white matter lesions, often with contrast enhancement, while ophthalmologic examination reveals retinal vascular abnormalities. Laboratory investigations may indicate renal or hepatic dysfunction but are generally nonspecific.
Definitive diagnosis requires genetic confirmation of a pathogenic mutation in the TREX1 gene.
The differential diagnosis is broad and includes primary central nervous system vasculitis, multiple sclerosis, CADASIL, Susac syndrome, and neoplastic processes.
Treatment
There is currently no curative or disease-modifying treatment for RVCL-S. Management is primarily supportive and requires a multidisciplinary approach. Ophthalmologic follow-up is essential for monitoring and managing retinal complications, while neurological symptoms are treated symptomatically. Renal and hepatic involvement should be managed according to standard clinical guidelines. Seizures, if present, are treated with antiepileptic medications. Importantly, immunosuppressive therapies have generally proven ineffective, as the disease is not primarily driven by inflammation. Experimental therapeutic approaches are under investigation, but no targeted treatments have yet been established.
Prognosis
RVCL-S is a progressive and ultimately life-limiting disorder. Patients experience a gradual accumulation of neurological deficits, worsening visual impairment, and increasing systemic involvement over time. The disease course varies but is generally characterized by steady deterioration. Median survival is estimated to be approximately 10 to 20 years after symptom onset, with death often resulting from neurological decline or complications related to multiorgan involvement.
