Hearing Outcomes in Stickler Syndrome: Variation Due to COL2A1 and COL11A1.

OBJECTIVES: Stickler syndrome (SS) is a heterogeneous inherited connective tissue disorder, often due to a mutation in COL2A1 or COL11A1. Mutations in these genes cause collagen abnormalities affecting ocular, auditory, orofacial, and skeletal systems, including hearing loss, micrognathia, and cleft palate. Understanding the variability of hearing phenotypes based on genetic mutation has a significant impact on treatment and long-term care. DESIGN: A retrospective chart review of pediatric patients with a confirmed diagnosis of SS between January 2003 and December 2018 at a tertiary pediatric hospital was performed. Patients were excluded if they did not have genetic evaluation, craniofacial/ear, nose, and throat evaluation, and/or audiologic testing. Charts were reviewed for the following information: age, race, sex, SS diagnosis, genetic variant of SS, and audiological testing data. RESULTS: There were 29 confirmed patients with SS who met criteria, 16 with type I (COL2A1) and 13 with type II (COL11A1). Of the 13 patients with type II, 12 (92%) demonstrated hearing loss, ranging in severity from mild to severe. In type I, 25% of patients had mild or resolved hearing loss. CONCLUSION: Results suggest that patients with type II SS are more likely to have congenital hearing loss than type I. Data also suggest that the COL11A1 mutation shows consistently more severe hearing loss than the COL2A1 mutation.

Incidence of mandibular distraction osteogenesis in Stickler Syndrome: Variation due to COL2A1 and COL11A1.

OBJECTIVE: To determine whether the two most common genetic mutations seen in Stickler Syndrome (SS) (COL2A1 and COL11A1) affect the incidence of mandibular distraction osteogenesis (MDO) and what impact Robin sequence (RS) has on diagnosis. SS is an autosomal dominant connective tissue disorder characterized by almost complete penetrance. COL2A1 and COL11A1 are the two most common mutations seen in SS patients. SS often presents at birth with RS, which is characterized by the triad of micrognathia, glossoptosis, and tongue-based airway obstruction. MDO is one surgical intervention that has been shown to be successful in relieving tongue base obstruction and is the surgical intervention of choice for this condition. METHODS: A retrospective chart review was performed on all patients with a diagnosis of SS at a tertiary pediatric hospital between January 1, 2003 and December 31, 2018. The included patient charts were reviewed for demographic information, SS mutation, and history of MDO. Forty-six patients had a clinical diagnosis of SS. Of those, 31 met inclusion criteria which involved having a molecular diagnosis of SS and sufficient follow up information to determine if MDO was indicated or performed. Twenty-two of the 31 included patients had a diagnosis of RS (70.96%). Thirteen of the 31 patients (41.94%) included in this study required MDO as a neonate. RESULTS: Fifty-percent of patients with type I (COL2A1) required MDO as a neonate compared to only 31% of patients with type II (COL11A1), though the difference between the two groups was not statistically significant. CONCLUSION: The findings of this study suggest that patients with type I mutation may have a higher incidence of MDO than patients with a type II mutation, though further research with larger sample sizes is needed. This information is helpful in counseling those with SS or family history of SS about what they can expect related to RS and need for MDO based on genetic findings. LEVEL OF EVIDENCE: 3.