Renal-Coloboma Syndrome

A rare familial syndrome combining ocular, renal and neurological signs.

Papillorenal Syndrome; Optic Nerve Coloboma with Renal Disease; Optic Coloboma, Vesicoureteral Reflux, and Renal Anomalies Syndrome; Coloboma-Ureteral-Renal Syndrome.

Unknown incidence. Autosomal dominant because of mutation in the PAX2 gene (a transcription factor known to play a critical role in embryogenesis and to be expressed in the developing eye, ear, kidney, ureteric bud, and midbrain/hindbrain) located on 10q24.3q25.1.

Ophthalmic and renal anomalies of this syndrome are most often bilateral, but highly variable. The mutations in the PAX2 gene lead to colobomatous eye defects. Developmental abnormalities of the optic fissure result in a group of defects including orbital cysts, microphthalmia, optic disc dysplasia, and colobomas of the optic nerve (sometimes referred to as “Morning Glory Disc Anomaly”) and retina at the posterior pole of the globe. (Iris colobomas have not been observed in patients with mutations in PAX2). Optic nerve colobomas involve the optic nerve head or optic papilla, and also result in thinning of the surrounding retinal epithelium, causing congenital blindness or loss of visual acuity, although not all patients with optic nerve colobomas have visual defects. Progressive deterioration of visual acuity over several decades has been described. The kidneys often appear small. The degree of renal disease is very variable, but the disease is usually progressive and often requires dialysis and/or renal transplant (although the age at end-stage renal disease is very variable). Patients with basically normal renal function have also been described. Renal biopsies may demonstrate mesangial fibrosis, glomerulosclerosis, glomerular hyalinization, hyperplastic glomeruli, tubular atrophy, and an overall rarefaction of glomeruli. Pathological examination of kidneys may find cortical thinning, hypoplastic papillae, a decreased number of glomeruli in the cortex and collecting ducts in the papilla, consistent with renal hypoplasia. Vesicoureteral reflux (VUR) is common in these children; however, it is not known to which extent VUR is responsible for the kidney changes described above. Some of these patients may also suffer from high-frequency hearing loss, central nervous system anomalies (seizure disorder, Arnold Chiari Syndrome Type I), joint laxity, and genital anomalies (cryptorchidism).

Preoperative laboratory investigations should include a complete cell blood count (CBC) (renal anemia), serum electrolytes, serum albumin (proteinuria), creatinine, and blood urea nitrogen. In case of end-stage renal disease, ask about the date of the last hemodialysis, residual urine production, and the daily maximal allowable amount to drink. Avoid potassium-containing intravenous solutions in these patients. Chronic antiepileptic treatment may interfere with the metabolism and elimination of anesthetic drugs.

CHARGE Syndrome: A life-threatening, congenital syndrome of multiple abnormalities, consisting of coloboma, heart disease, choanal atresia, mental and growth retardation, genital and urinary anomalies, and ear anomalies with deafness. The prognosis worsens if the disorder is associated with concomitant cyanotic congenital heart disease, central nervous system anomalies, and esophageal atresia.

COACH Syndrome: An inherited syndrome characterized by the combination of hepatic fibrosis, early-onset ataxia, cerebellar aplasia, oligophrenia, and coloboma.

Joubert Syndrome: A genetic disorder characterized by cerebral malformations (vermis and brainstem) resulting in severe coordination (ataxia) and breathing (sleep apnea, hyperpnea) disorders.

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