Symmetrical Chorioretinal Colobomata with Craniovertebral Junction Anomalies in CHARGE Syndrome - A Case Report with Review of Literature
A 27-year-old woman presented with complaints of poor vision in both eyes and inability to hear since birth. She had undergone surgical ligation of patent ductus arteriosus (PDA) in childhood. There was no feeding difficulty in childhood. She had retarded growth and development and a characteristic facial appearance. There was bilateral Grade I/II microtia [].\nHer vision was 20/2000 in both eyes. Ocular adnexa, ocular motility, and anterior segment were normal in both eyes. There was no iris coloboma but symmetrical, large colobomata involving the optic nerve, choroid, and retina were present [Figure and ]. The colobomata included the macula. There were no neurological dysfunction or limb abnormalities.\nThere was severe to profound sensorineural deafness on pure tone audiometry examination and brain stem evoked response audiometry with identifiable peak V on 125 dB stimulus in both ears. Echocardiography revealed normal cardiac chamber dimensions and valve morphology with no residual shunt across PDA closure.\nUltrasound examination of the abdomen revealed an infantile uterus. X-ray KUB (kidney, urether, and bladder) region and serum calcium were within normal limits.\nMagnetic resonance imaging (MRI) revealed bilateral hypoplasia of vestibule, lateral semicircular canals, and cochlea with visualization of about 1½-turns [Figure and ]. Vestibulo-cochlear nerves on both sides were of smaller size than the adjacent facial nerves with narrow internal acoustic meatus. There was basilar invagination with short clivus, fused C2 and C3 vertebrae, and partially occipitalized atlas []. There was a large posterior global defect with adjacent deformed and thinned out sclera around the optic disc in both eyes []. The brain was normal.\nChromosomal analysis revealed normal female karyotype (46 XX chromosomes) in all the metaphases analyzed. CHD7 gene analysis could not be done.\nA diagnosis of CHARGE syndrome was arrived at by satisfying three major criteria prelisted by Blake et al., namely, i) Coloboma (retina and choroid), ii) Characteristic ear abnormalities, and iii) Cranial nerve dysfunction (sensorineural deafness), plus three minor criteria, namely, i) Cardiovascular malformations, ii) Growth deficiency, and iii) Distinctive face. The criteria for typical CHARGE syndrome according to Verloes are also met, namely, two major criteria of i) Coloboma (choroid) and ii) Hypoplastic semi-circular canals, plus three minor criteria of i) Rhombencephalic dysfunction (sensorineural deafness), ii) Abnormal external ear, and iii) Malformation of mediastinal organs (heart).\nProphylactic laser retinopexy was done in both the eyes along the border of the coloboma to reduce the risk of future retinal detachments. Her corrected visual acuity was 20/2000 in both eyes.\nHer two sisters and mother were found to be normal.