Table 2.

Audiological, clinical and family histories of biallelic STRC mutation patients

No.	Onset	Audiological descriptiona	Clinical description	Family history of HL
Patients with homozygous STRC deletions
1	2 years	HL in all frequencies with mild HL in low- to mid-frequencies until 4 kHz, moderate to severe HL to 8 kHz	No additional symptoms	None; parents are confirmed heterozygous deletion carriers
2	Childhood	High tone HL, no further description available	Delayed speech and language development	Sister has HL since birth; two additional sisters are without HL; maternal grandmother and paternal grandfather have reported age-related HL
95	Birth	Auditory brainstem response measurements from the newborn hearing test indicated maximal thresholds of 65 dB	Born in the 35th week of gestation presenting facial dysmorphisms (long eye lashes, flat nasal bridge, and epicanthus), hypoplastic widely spaced nipples, atrial septal defect, and delayed speech development; also diagnosed with hydroxylysinuria, hydroxylysinemia, and severe recurrent infections	No family history of HL; parents are first-degree cousins and confirmed heterozygous deletion carriers; one sibling died at 3 months because of an infection of unknown etiology
Patients with STRC deletion and pathogenic DNA sequence mutation
3	5 years	Audiogram from age 10 indicated moderate HL, mildly sloping at higher frequencies	Oral motor skills and vocabulary developed normally per age; bifid uvula and sigmatism interdentalis diagnosed at 5 years of age; underwent intensive ambulant therapy for 1 year for dyslalia	Family history of HL
4	3 years	High frequency HL with normal hearing thresholds until 1 kHz and mild to moderate HL from 2 to 8 kHz	None available	None
6	Birth	Mild to middle grade HL; free field and PTA between 2 and 4 years of age demonstrated mild HL in all frequencies and sloping audiometric profiles, more pronounced between 2 and 8 kHz	Hypothyroidism with HL prompted Pendred syndrome screening with SLC26A4 mutation negative result	None
Patient with compound heterozygous DNA sequence mutations
24	6 years	PTA with sloping high frequency configuration in the right ear and cookie bite pattern in the left ear	No additional symptoms	Father and paternal uncle have mild HL; parents are first-degree cousins with two additional normally hearing children

HL, hearing loss; PTA, pure tone audiometry.

^aAll patients are bilaterally affected.