No abstract

Riboflavin transporter deficiency (RTD) is a rare genetic disorder that can have detrimental effects on the nervous system, causing progressive neurodegeneration. Here, we report the second case of RTD in Saudi Arabia. An 18-month-old boy presented to the otolaryngology clinic with six weeks history of progressive noisy breathing associated with drooling, choking, and difficulty in swallowing. Progressive regression of the child's motor and communicative abilities was reported as well. Upon examination, the child had biphasic stridor, chest retractions, bilateral facial palsy, and hypotonia. The presence of an aerodigestive foreign body or congenital anomalies was excluded using bronchoscopy and esophagoscopy. Empirical highdose riboflavin replacement therapy was initiated upon anticipation of diagnosis. Whole exome sequencing revealed a SLC52A3 gene mutation, which confirmed the diagnosis of RTD. After a period of intensive care unit (ICU) admission with endotracheal intubation, the child's general condition improved, and he was weaned off of respiratory support. Tracheostomy was avoided in this patient, as he responded to riboflavin replacement therapy. During the disease course, an audiological assessment revealed severe bilateral sensorineural hearing loss. He was discharged home on gastrostomy feeding owing to the risk of frequent aspiration, and he was regularly followed up by the swallowing team. The early initiation of high-dose riboflavin replacement appears to be of great value. The benefits of cochlear implants in RTD have been reported, but not fully established. This case report will increase awareness in the otolaryngology community about patients with this rare disease who might initially present to the clinic with an otolaryngology-related complaint.

The lingual frenulum (LF) is a fold of tissue that connects the tongue to the oral cavity's floor. Abnormal frenula are associated with speech alterations. The absence of the LF is associated with Ehler's Danlos syndrome (EDS). In this case report, we present a premature infant incidentally found to have an absent lingual frenulum, with recurrent desaturations during feeding. The desaturations were believed to be due to the absent lingual frenulum, but they resolved after one month without treatment and were then attributed to apnea of prematurity. Whole exome sequence showed no genetic disorders. The infant is now doing well with no interventions. An absent lingual frenulum warrants molecular genetic testing for EDS. However, it does not warrant any treatment; special considerations are only required during intubation.