Simultaneous Bilateral Cochlear Implantation in a Child with Warsaw Breakage Syndrome and Normal Cochlear Morphology: A Case Report and Focused Literature Review

Background and Clinical Significance: Warsaw Breakage Syndrome (WABS), also termed DDX11-related cohesinopathy, is an exceptionally rare autosomal recessive disorder caused by biallelic pathogenic variants in DDX11. Sensorineural hearing loss is a recurrent manifestation and has frequently been reported together with structural abnormalities of the cochlea or cochlear nerve. Published experience with cochlear implantation in WABS remains extremely limited. Case Presentation: A 2.5-year-old boy was referred because of absent spoken-language development and limited responses to environmental and speech sounds. Newborn hearing screening had not been performed. After treatment of bilateral middle-ear effusions, comprehensive audiological assessment showed absent transient-evoked otoacoustic emissions and cochlear microphonics, no reproducible auditory brainstem response waveforms at the maximum tested level of 90 dB nHL, and auditory steady-state response estimates in the severe-to-profound range bilaterally. Clinical examination revealed microcephaly, short stature, and global developmental delay, raising suspicion of an underlying syndromic disorder. High-resolution computed tomography demonstrated normal cochlear morphology, while magnetic resonance imaging showed bilaterally visualized cochlear nerves without aplasia or marked hypoplasia. Whole-exome sequencing identified a pathogenic frameshift variant in DDX11 in apparent homozygosity, supporting the molecular diagnosis of WABS. Simultaneous bilateral cochlear implantation was performed at 3 years of age without complications. Longitudinal auditory development, assessed with the LittlEARS Auditory Questionnaire, improved from 0/35 at activation to 10/35 at 8 months, 21/35 at 20 months, and 33/35 at 24 months of auditory age. At approximately 30 months of auditory age, structured language assessments demonstrated further receptive and expressive communication gains, although language development remained influenced by the underlying neurodevelopmental disorder. At 33 months of auditory age, functional auditory performance assessed with PEACH-GR was 90% in quiet, 80% in noise, and 85% overall, while Greek-standardized language testing demonstrated persistent language difficulties relative to chronological-age expectations. Conclusions: Severe-to-profound prelingual sensorineural hearing loss in WABS may occur despite normal cochlear morphology and bilaterally visualized cochlear nerves. In this patient, simultaneous bilateral cochlear implantation was technically uncomplicated. During subsequent bilateral device use, programming, rehabilitation, and maturation, quantitatively documented progressive auditory development and functional communication gains were observed. Comprehensive audiological, radiological, genetic and developmental assessment is essential for individualized implant candidacy and realistic family counseling.