Page 99 - Clinical variability in Noonan syndrome with emphasison ear and eye

COCHLEAR IMPLANTATION IN NOONAN SYNDROME AND NOONAN SYNDROME WITH MULTIPLE LENTIGINES
Table 1. Overview of all NS and NSML patients in the current study and the literature with CI.
Patient
1 2 3 4 5 6 7 8
Authors
Current study Current study Current study Current study Scheiber et al (19) Scheiber et al (19) Current study Ho-Suk Chu et al (20)
Syndrome Gene
NS PTPN11 NS PTPN11 NS PTPN11 NS PTPN11 NS PTPN11 NS PTPN11 NSML PTPN11 NSML PTPN11
Nucleotide change
1510A>G 124A>G 922A>G 124A>G 922A>G 853T>C 836A>G 1381G>A
Amino acid change
Met504Val Thr42Ala Asn308Aps Thr42Ala Asn308Asp Phe285Leu Tyr279Cys Ala461Thr
NS = Noonan Syndrome, NSML = Noonan syndrome with multiple lentigines, CI = cochlear implantation.
a variable degree of neurocognitive delay. Pre-implantation, the status of the mastoid pneumatization and the associated inner ear abnormalities should be evaluated carefully because structural anomalies of the inner ear and petrous bone have been reported in patients with NS and NSML (23, 24). However, in all our patients, the anatomy of the temporal bone was normal. With different surgical techniques, a CI was possible in these cases and even with a good outcome. In general, up to 55% of all NS patients have a mild to moderate bleeding tendency. Severe hemorrhage occurs in 3% of all patients with NS (6). Special care might be required to prevent intra-operative and post- operative hemorrhage. In the current study, two out of the four NS patients had mild hemorrhage during the operation, and one patient had a hemostasis disorder. This is important to keep in mind before surgery. In both syndromes, variable cognitive deficits are described. Intellectual disability is present in 15-35% of all patients with NS and is usually mild (6). Four of our patients had an intellectual disability. However, the degree was variable. In 30% of all NSML cases, an intellectual disability is observed (25). This was not the case in our NSML patient. Because of the possibility of neurocognitive delay due to auditory deprivation, early hearing rehabilitation seems to be even more important in cases of such intellectually disabled children with hearing loss.
Conclusion
Appropriate knowledge of the phenotype-genotype correlations and of the outcome of cochlear implantation in genetic hearing impairment is important in the work-up to a CI. CI surgery in NS patients might be challenging because of the abnormal anatomy, hemorrhage and neurocognitive delay. However, acceptable but variable results are presented in these case series.
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