Loken Senior Syndrome

Inherited disorder characterized by rapidly progressive renal insufficiency (nephronophthisis) and eye disease (retinitis pigmentosa).

Familial Juvenile Nephronophthisis with Associated Ocular Anomaly; Hereditary Renal Dysplasia-Blindness; Renal Dysplasia-Retinal Aplasia, Loken-Senior type; Familial Renal-Retinal Dystrophy; Renal-Retinal Syndrome; Senior-Biochi Syndrome; Senior-Loken Syndrome.

Incidence of all nephrophthisis disorders is approximately 1:1,000,000 population in the United States and still more in Europe. No racial predilection; both sexes are equally affected.

Autosomal recessive. Gene map locus mostly unknown. Candidate loci are 1p36, 2q12-q13, and 15q.

The function of α6 integrin is defective. Probably as a compensatory mechanism, there is also an abnormal expression of the α5 integrin fibronectin receptor in the tubular basement membrane. This process may lead to destruction of the tubular basement membrane, resulting in gradual loss of kidney function and development of cysts in the renal medulla.

Renal insufficiency and severe normocytic and normochromic anemia. Serum erythropoietin concentration is lower than in patients with other progressive renal diseases. Laboratory findings indicative of renal failure: metabolic acidosis, hypocalcemia, hyperphosphatemia, elevated serum BUN and creatinine concentrations. Imaging studies showing multiple cysts, typically in the medulla and corticomedullary region. Ophthalmoscopy and electroretinography are consistent with tapetoretinal degeneration. Renal biopsy shows typical lesions. The prognosis is poor (death before age 10 years in most patients).

Symptoms include high urine output (patient cannot concentrate the urine), nocturia, headache, anorexia, progressive weakness, and weight loss. The disease progresses from chronic renal failure to end-stage renal disease. No curative treatment is available except for renal transplant.

Check severity of renal failure (blood and urine tests). Request preoperative dialysis in patient with severe renal insufficiency. Check red blood cell count. Consider preoperative treatment with erythropoietin to improve anemia. Preoperative eye examination is recommended.

Presence of chronic renal failure leads to increased sensitivity to opioid analgesic agents. Danger of fluid overload (or hypovolemia after dialysis therapy). Severe anemia may require intraoperative transfusion.

Unable to metabolize nitroprusside.

Saldino-Mainzer Syndrome (Conorenal Syndrome; Retinal Pigmentary Dystrophy-Cerebral Ataxia-Skeletal Dysplasia Syndrome): Characterized by chronic renal failure and the presence of prominent cone-shaped epiphyses in the distal phalanges and cone-shaped epiphyses in the middle phalanges of the hands. The clinical association has led to name this medical condition as “conorenal syndrome." Other clinical features include retinitis pigmentosa, cerebellar ataxia, nephronophthisis (medullary cystic kidney disease), often evolving to end-stage renal disease. Percutaneous renal biopsy showed global scarring and acellularity of many glomeruli in both sibs.

Polycystic Kidney Disease (PKD): Usually with congenital hepatic fibrosis and prone to result in severe renal failure.