John H. Greinwald

Laryngomalacia and Its Treatment

Objective: To determine 1) airway outcome of infants with laryngomalacia who do not undergo routine direct laryngoscopy (DL) and bronchoscopy (B), 2) the age at resolution of laryngomalacia, and, 3) outcome of supraglottoplasty as a function of the type of laryngomalacia and the presence of concomitant disease.

A multicenter study of the frequency and distribution of GJB2 and GJB6 mutations in a large North American cohort

Purpose: The aim of the study was to determine the actual GJB2 and GJB6 mutation frequencies in North America after several years of generalized testing for autosomal recessive nonsyndromic sensorineural hearing loss to help guide diagnostic testing algorithms, especially in light of molecular diagnostic follow-up to universal newborn hearing screening.Methods: Mutation types, frequencies, ethnic distributions, and genotype-phenotype correlations for GJB2 and GJB6 were assessed in a very large North American cohort.Results: GJB2 variants were identified in 1796 (24.3%) of the 7401 individuals examined, with 399 (5.4%) homozygous and 429 (5.8%) compound heterozygous. GJB6 deletion testing was performed in 12.0% (888/7401) of all cases. The >300-kb deletion was identified in only nine individuals (1.0%), all of whom were compound heterozygous for mutations in GJB2 and GJB6. Among a total of 139 GJB2 variants identified, 53 (38.1%) were previously unreported, presumably representing novel pathogenic or benign variants.Conclusions: The frequency and distribution of sequence changes in GJB2 and GJB6 in North America differ from those previously reported, suggesting a considerable role for loci other than GJB2 and GJB6 in the etiology of autosomal recessive nonsyndromic sensorineural hearing loss, with minimal prevalence of the GJB6 deletion.Purpose: To determine short–term effects of intravitreal bevacizumab for subfoveal choroidal neovascularization (CNV) in pathologic myopia. Methods: In this prospective interventional case series, patients were treated with 2.5 mg of intravitreal bevacizumab and followed for 3 months. Best-corrected visual acuity (BCVA), optical coherence tomography (OCT), and fluorescein angiography (FA) were recorded. Indications for retreatment were active leaking CNV shown by FA and presence of subretinal fluid by OCT in combination with visual disturbances. Results: Fourteen patients were included, with a mean age of 53.86 ± 16.26 years (range 29–85). Mean spherical equivalent was −13.87 ± 3.68 diopters (−7.25 to −20.50). Minimum follow-up was 3 months. There were no adverse events. The mean initial visual acuity was 20/200 improving to 20/100 at 2 weeks, 20/80 at 4 weeks, and 20/60 at 8 and 12 weeks (P = 0.007; P = 0.001; P = 0.005; P = 0.001, respectively). Initial foveal thickness improved from 385.43 &mgr;m ± 125.83 &mgr;m to 257.64 ± 76.6 &mgr;m and 194.54 ± 54.35 &mgr;m after the first and third month, respectively (P = 0.001). Conclusions: Initial treatment results of patients with CNV due to pathologic myopia did not reveal any short-term safety concerns. Intravitreal bevacizumab resulted in a significant decrease in foveal thickness and improvement in visual acuity. These favorable initial results support further larger and long-term studies.

Molecular analysis of the mitochondrial 12S rRNA and tRNASer(UCN) genes in paediatric subjects with non-syndromic hearing loss

Hearing loss is a very common congenital disorder affecting one in 1000 newborns. More than 50% of deafness cases in the paediatric population have a genetic cause with autosomal dominant, autosomal recessive, X-linked, or mitochondrial patterns of inheritance.1 Mutations in mitochondrial DNA (mtDNA), particularly in the 12S rRNA and tRNASer(UCN) genes, have been found to be one of the most important causes of sensorineural hearing loss (SNHL).2,3 The homoplasmic A1555G mutation in the highly conserved decoding site of the mitochondrial 12S rRNA has been found to be associated with both aminoglycoside-induced and non-syndromic SNHL in many families of different ethnic origins.4–8 Recently, the homoplasmic C1494T mutation in the same gene has also been found to be associated with aminoglycoside-induced and non-syndromic SNHL in a large Chinese family.9 In addition, a C-insertion or deletion at position 961 of the 12S rRNA gene has been shown to be associated only with aminoglycoside-induced deafness.10,11 Furthermore, the mitochondrial tRNASer(UCN) appears to be another hot spot for mutations associated with hearing impairment, as five deafness-associated mutations have been identified in the mitochondrial tRNASer(UCN) gene: A7445G,12,13 7472insC,14 T7510C,15 T7511C,16 and T7512C.17 However, non-syndromic deafness-associated mtDNA mutations, such as the A1555G4–8 or A7445G12,13 mutation, are often not sufficient to produce the clinical phenotype since some individuals carrying these mutations have normal hearing. Thus, other factors including other mtDNA mutations/polymorphisms and/or nuclear backgrounds or environmental factors modulate the phenotypic variability and penetrance of deafness associated with these mtDNA mutations. ### Key points

Treatment of lymphangiomas in children: an update of Picibanil (OK-432) sclerotherapy.

Picibanil (OK-432) is a sclerosing agent derived from a low-virulence strain of Streptococcus pyogenes that induces regression of macrocystic lymphangiomas. This report describes a prospective, nonrandomized trial to evaluate the efficacy of Picibanil in the treatment of 13 affected children ranging in age from 1 to 94 months. On average, 4.1 fluoroscopically guided intracystic injections were performed per child, with an average total dose of 0.56 mg of Picibanil. As judged by physical examination and radiographic studies, 5 children (42%) showed a complete or substantial response, and 2 children (16%) showed an intermediate response. No response was seen in 5 children (42%), 2 of whom had massive craniofacial lymphangioma. Factors that contribute to failure with Picibanil sclerotherapy are the presence of a significant micro-cystic component to the lesion, massive craniofacial involvement, and previous surgical resection. Macrocystic lymphangiomas of the infratemporal fossa or cervical area have the best response to therapy.

Enlarged vestibular aqueduct syndrome in the pediatric population.

Objective To correlate clinical and audiometric findings with the radiologic appearance in patients with enlarged vestibular aqueduct. Design A retrospective review of data from enlarged vestibular aqueduct patients identified in a pediatric hearing-impaired database of 1,200 patients. Setting A tertiary care pediatric referral center. Patients Subjects were included for study with a radiographic diagnosis of enlarged vestibular aqueducts in at least one ear by a pediatric neuroradiologist. Main Outcome Measures Audiometric evaluations and radiographic temporal bone measurements. Results Seventy-seven patients were identified with an enlarged vestibular aqueduct with a male-to-female ratio of 1:1.5. Patients were followed for a mean of 34 months (range, 0–179 months). Hearing loss was bilateral in 87% of cases. Vestibular symptoms were present in only three (4%) of the patients. Three patients (4%) suffered a sudden decrease in hearing after mild head trauma. Borderline enlargement of the vestibular aqueduct was associated with varying degrees of sensorineural hearing loss. Ninety-seven percent (64 of 66) of ears in control subjects with no sensorineural hearing loss had normal vestibular aqueduct measurements at the midpoint and operculum. Overall, the audiogram remained stable in 51% of ears, fluctuated in 28%, and progressively worsened in 21%. Measurements of the vestibular aqueduct at the midpoint and the operculum did not correlate with the audiometric threshold or the audiogram configuration. However, mean vestibular aqueduct size at the operculum was significantly larger in those with a progressive loss when compared with those with a fluctuating or stable hearing outcome. Conclusions Overall, audiometric thresholds remained generally stable, with sudden deterioration of hearing after head trauma seen in only three male patients. Progression of hearing loss after head trauma was not a significant finding in our patient population. Vestibular aqueduct opercular size alone showed a direct correlation with the audiometric outcome. Borderline enlarged vestibular aqueduct measurements appear to be associated with sensorineural hearing loss.

Cosegregation of the G7444A Mutation in the Mitochondrial COI/tRNASer(UCN) Genes with the 12S rRNA A1555G Mutation in a Chinese Family with Aminoglycoside-induced and Nonsyndromic Hearing Loss

We report here on the characterization of a three‐generation Chinese family with aminoglycoside‐induced and nonsyndromic hearing impairment. Ten of 17 matrilineal relatives exhibited bilateral and sensorineural hearing impairment. Of these, nine matrilineal relatives, who had a history of exposure to aminoglycosides, exhibited variable severity and audiometric configuration of hearing loss. The dose and age at the time of drug administration seemed to be correlated with the severity of the hearing loss experienced by affected individuals. Sequence analysis of the complete mitochondrial genome in the pedigree showed the presence of homoplasmic A1555G mutation and 37 variants belonging to haplogroup D4a. Of those variants, the G7444A mutation is of special interest as the mutation at this position results in a read‐through of the stop condon AGA of the COI message, thereby adding three amino acids (Lys–Gln–Lys) to the C‐terminal of the polypeptide. Alternatively, the G7444A mutation is adjacent to the site of 3′ end endonucleolytic processing of L‐strand RNA precursor, spanning tRNASer(UCN) and ND6 mRNA. Thus, the G7444A mutation, similar to the deafness‐associated A7445G mutation, may lead to a defect in the processing of the L‐strand RNA precursor, thus influencing the phenotypic expression of the A1555G mutation. These data also imply that nuclear background plays a role in the aminoglycoside ototoxicity associated with the A1555G mutation in this Chinese pedigree.

Pediatric cochlear implantation in auditory neuropathy.

Objective Auditory neuropathy (AN) is characterized by varying degrees of sensorineural hearing loss, an absent or severely abnormal auditory brainstem response, and normal otoacoustic emissions. The nomenclature for this condition reflects the concept that the site of lesion is proximal to the cochlea (e.g., cochlear nerve). Given this hypothesis, it is reasonable to expect limited benefit from cochlear implantation in patients with AN. However, a growing body of evidence shows the striking benefits of cochlear implantation in AN. To explore this topic, we reviewed our population of children with AN and, specifically, the performance results in those children having undergone cochlear implantation. Study Design A retrospective case review of those patients diagnosed with AN from 1993 to 2001. Setting A tertiary pediatric referral center. Patients A diagnosis of AN reported from the Center for Hearing and Deafness Research, Cincinnati, OH, database. Results Eighteen patients were diagnosed with AN (11 girls, 7 boys), with 3 sets of siblings, including 1 set of identical twins. Four patients with AN underwent implantation in the previous 5 years. Twelve out of the 18 patients had classic risk factors for AN (e.g., prematurity and hyperbilirubinemia). The degree of hearing loss varied in our patients, with a majority showing severe to profound deficits. All children with implants showed improvement in auditory and verbal development, but this improvement was variable. Conclusion The success of cochlear implantation in these patients suggests that some children with AN have an auditory system lesion that can be compensated for by cochlear implantation. This implies either an inner hair cell or inner hair cell–cochlear nerve junctional pathology that can be overcome by direct electrical stimulation.

A diagnostic paradigm for childhood idiopathic sensorineural hearing loss.

OBJECTIVE: Our objective was to determine the diagnostic yield of laboratory testing, radiological imaging, and GJB2 mutation screening in a large cohort of patients with differing severities of idiopathic sensorineural hearing loss (SNHL). DESIGN AND SETTING: We undertook a retrospective study of patients presenting with SNHL at our institution from 1993 to 2002. RESULTS: Laboratory testing had an extremely low yield. Patients with unilateral SNHL had a significantly higher imaging yield than those with bilateral. The diagnostic yield of GJB2 screening was significantly higher in patients with severe to profound SNHL than in those with less severe SNHL. However, a relatively large number of patients with mild to moderate SNHL had positive GJB2 screens. CONCLUSIONS: Based on diagnostic yields, we propose a cost-effective stepwise diagnostic paradigm to replace the more commonly used and costly simultaneous testing approach. EBM rating: C. (Otolaryngol Head Neck Surg 2004;131: 804–9.)

The large vestibular aqueduct: A new definition based on audiologic and computed tomography correlation:

Objective The study goal was to determine the prevalence and clinical significance of a large vestibular aqueduct (LVA) in children with sensorineural hearing loss (SNHL). Study Design and Setting We conducted a retrospective review of a pediatric SNHL database. One hundred seven children with SNHL were selected and their radiographic and audiometric studies were evaluated. Radiographic comparisons were made to a group of children without SNHL. Results A vestibular aqueduct (VA) larger than the 95th percentile of controls was present in 32% of children with SNHL. Progressive SNHL was more likely to occur in ears with an LVA and the rate of progressive hearing loss was greater than in ears without an LVA. The risk of progressive SNHL increased with increasing VA size as determined by logistic regression analysis. Conclusions An LVA is defined as one that is ≥2mm at the operculum and/or ≥1 mm at the midpoint in children with nonsyndromic SNHL. An LVA appears to be more common than previously reported in children with SNHL. A linear relationship is observed between VA width and progressive SNHL. Significance The finding of an LVA in children with SNHL provides diagnostic as well as prognostic information.

High-throughput detection of mutations responsible for childhood hearing loss using resequencing microarrays

BackgroundDespite current knowledge of mutations in 45 genes that can cause nonsyndromic sensorineural hearing loss (SNHL), no unified clinical test has been developed that can comprehensively detect mutations in multiple genes. We therefore designed Affymetrix resequencing microarrays capable of resequencing 13 genes mutated in SNHL (GJB2, GJB6, CDH23, KCNE1, KCNQ1, MYO7A, OTOF, PDS, MYO6, SLC26A5, TMIE, TMPRSS3, USH1C). We present results from hearing loss arrays developed in two different research facilities and highlight some of the approaches we adopted to enhance the applicability of resequencing arrays in a clinical setting.ResultsWe leveraged sequence and intensity pattern features responsible for diminished coverage and accuracy and developed a novel algorithm, sPROFILER, which resolved >80% of no-calls from GSEQ and allowed 99.6% (range: 99.2-99.8%) of sequence to be called, while maintaining overall accuracy at >99.8% based upon dideoxy sequencing comparison.ConclusionsTogether, these findings provide insight into critical issues for disease-centered resequencing protocols suitable for clinical application and support the use of array-based resequencing technology as a valuable molecular diagnostic tool for pediatric SNHL and other genetic diseases with substantial genetic heterogeneity.