Answer for BIR CoW 08 May 2022
Renal Coloboma Syndrome
Findings
B-mode ultrasound of abdomen reveals contracted right kidney with renal parenchymal echogenicity equal to that of renal sinuses suggestive bilateral grade 3 renal parenchymal changes B-mode ultrasound of both orbits reveals defect in the posterior aspect of globe at the level of insertion of optic disc head showing herniation of vitreous with a defect measuring 0.67 cm in width and 0.78 cm in depth on the right side and 0.57 cm in width and 0.31 cm in depth on the left side. Axial T2 SPIR sequence of orbits and FFE sequence of brain shows a focal posterior defect at the level of optic disc forming a retrobulbar fluid cyst with vitreous herniation within noted on the right side. A focal posterior defect at the level of optic disc also noted on the left side suggestive of coloboma. Optical coherence tomography of orbit revealed retinochoroidoscleral excavation with a fine layer of retina covering the sclera with cystic edema temporal to optic disc coloboma.
Discussion
Renal coloboma syndrome (RCS) also known as papillorenal syndrome describes a condition consisting of optic nerve dysplasia (frequently described as a coloboma) and renal malformations.. It is characterized primarily by ocular signs (77%) and renal manifestations (92%). The renal features are part of a spectrum of malformations termed congenital anomalies of the kidney and urinary tract (CAKUT). To date, PAX2 mutations have been the only identified genetic cause associated with RCS. The most common renal manifestation is renal hypodysplasia, which is usually bilateral and presented in 65% of involved individuals. Other renal abnormalities include renal insufficiency, cystic kidney disease, vesicoureteral reflux, and other CAKUT. Histologically, the kidneys show less than normal number of glomeruli with glomerular hypertrophy indicative of oligomeganephronia.Eye abnormalities include optic nerve dysplasia and coloboma, which comprise around 72% of patients, and other findings include retinal coloboma, optic nerve cyst, macular abnormalities, or lens abnormalities. Consequences of the renal hypodysplasia include hypertension, proteinuria and renal insufficiency that frequently progresses to end-stage kidney disease. Consequences of the ocular malformations include decreased visual acuity, blindness and retinal detachment. Reported non-renal and non-ophthalmological manifestations include high-frequency sensorineural hearing loss (7%), short stature, developmental delay, autism, CNS malformations (e.g., Chiari I malformation), hyperuricemia, soft skin, joint laxity, elevated pancreatic amylase, and short digits.
REFERENCES
Schimmenti, L. Renal coloboma syndrome. Eur J Hum Genet 19, 1207–1212 (2011). doi.org/10.1038/ejhg.2011.102 Schimmenti LA, Pierpont ME, Carpenter BL, Kashtan CE, Johnson MR, Dobyns WB : Autosomal dominant optic nerve colobomas, vesicoureteral reflux, and renal anomalies. Am J Med Genet 1995; 59: 204–208.doi: 10.1002/ajmg.1320590217
Findings
B-mode ultrasound of abdomen reveals contracted right kidney with renal parenchymal echogenicity equal to that of renal sinuses suggestive bilateral grade 3 renal parenchymal changes B-mode ultrasound of both orbits reveals defect in the posterior aspect of globe at the level of insertion of optic disc head showing herniation of vitreous with a defect measuring 0.67 cm in width and 0.78 cm in depth on the right side and 0.57 cm in width and 0.31 cm in depth on the left side. Axial T2 SPIR sequence of orbits and FFE sequence of brain shows a focal posterior defect at the level of optic disc forming a retrobulbar fluid cyst with vitreous herniation within noted on the right side. A focal posterior defect at the level of optic disc also noted on the left side suggestive of coloboma. Optical coherence tomography of orbit revealed retinochoroidoscleral excavation with a fine layer of retina covering the sclera with cystic edema temporal to optic disc coloboma.
Discussion
Renal coloboma syndrome (RCS) also known as papillorenal syndrome describes a condition consisting of optic nerve dysplasia (frequently described as a coloboma) and renal malformations.. It is characterized primarily by ocular signs (77%) and renal manifestations (92%). The renal features are part of a spectrum of malformations termed congenital anomalies of the kidney and urinary tract (CAKUT). To date, PAX2 mutations have been the only identified genetic cause associated with RCS. The most common renal manifestation is renal hypodysplasia, which is usually bilateral and presented in 65% of involved individuals. Other renal abnormalities include renal insufficiency, cystic kidney disease, vesicoureteral reflux, and other CAKUT. Histologically, the kidneys show less than normal number of glomeruli with glomerular hypertrophy indicative of oligomeganephronia.Eye abnormalities include optic nerve dysplasia and coloboma, which comprise around 72% of patients, and other findings include retinal coloboma, optic nerve cyst, macular abnormalities, or lens abnormalities. Consequences of the renal hypodysplasia include hypertension, proteinuria and renal insufficiency that frequently progresses to end-stage kidney disease. Consequences of the ocular malformations include decreased visual acuity, blindness and retinal detachment. Reported non-renal and non-ophthalmological manifestations include high-frequency sensorineural hearing loss (7%), short stature, developmental delay, autism, CNS malformations (e.g., Chiari I malformation), hyperuricemia, soft skin, joint laxity, elevated pancreatic amylase, and short digits.
REFERENCES
Schimmenti, L. Renal coloboma syndrome. Eur J Hum Genet 19, 1207–1212 (2011). doi.org/10.1038/ejhg.2011.102 Schimmenti LA, Pierpont ME, Carpenter BL, Kashtan CE, Johnson MR, Dobyns WB : Autosomal dominant optic nerve colobomas, vesicoureteral reflux, and renal anomalies. Am J Med Genet 1995; 59: 204–208.doi: 10.1002/ajmg.1320590217
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!