Periodontal Disease in Rare Renal Disorders (PERIO-RA-RE)

Inclusion Criteria: * Age ≥18 years * Ability to provide written informed consent * At least 10 natural teeth present * Belonging to one of the predefined study groups: 1. Alport syndrome (genetically or clinically confirmed) 2. Fabry disease (enzymatically or genetically confirmed) 3. Tuberous sclerosis complex (according to established clinical or genetic criteria) 4. Systemic lupus erythematosus defined according to the 2019 EULAR/ACR or SLICC 2012 classification criteria, with renal involvement defined by at least one of the following: \[1\] Biopsy-proven lupus nephritis, \[2\] Persistent proteinuria (\>0.5 g/day or equivalent), \[3\] Active urinary sediment (hematuria and/or cellular casts) consistent with lupus nephritis 5. Chronic kidney disease (CKD) of non-rare etiology: defined according to KDIGO criteria (eGFR \<60 ml/min/1.73 m² and/or markers of kidney damage) 6. Individuals without CKD, recruited from clinical or dental care settings as non-CKD controls Exclusion Criteria: * Periodontal treatment within the last 6 months * Antibiotic therapy within the last 4 weeks * Pregnancy * Conditions precluding periodontal examination * Inability to comply with study procedures