In-depth characterisation of a cohort of individuals with missense and loss-of-function variants disrupting FOXP2.

BACKGROUND: Heterozygous disruptions of FOXP2 were the first identified molecular cause for severe speech disorder: childhood apraxia of speech (CAS), and yet few cases have been reported, limiting knowledge of the condition. METHODS: Here we phenotyped 28 individuals from 17 families with pathogenic FOXP2-only variants (12 loss-of-function, five missense variants; 14 males; aged 2 to 62 years). Health and development (cognitive, motor, social domains) were examined, including speech and language outcomes with the first cross-linguistic analysis of English and German. RESULTS: Speech disorders were prevalent (23/25, 92%) and CAS was most common (22/25, 88%), with similar speech presentations across English and German. Speech was still impaired in adulthood, and some speech sounds (eg, 'th', 'r', 'ch', 'j') were never acquired. Language impairments (21/25, 84%) ranged from mild to severe. Comorbidities included feeding difficulties in infancy (10/26, 38%), fine (13/26, 50%) and gross (13/26, 50%) motor impairment, anxiety (5/27, 19%), depression (6/27, 22%) and sleep disturbance (10/24, 42%). Physical features were common (22/27, 81%) but with no consistent pattern. Cognition ranged from average to mildly impaired and was incongruent with language ability; for example, seven participants with severe language disorder had average non-verbal cognition. CONCLUSIONS: Although we identify an increased prevalence of conditions like anxiety, depression and sleep disturbance, we confirm that the consequences of FOXP2 dysfunction remain relatively specific to speech disorder, as compared with other recently identified monogenic conditions associated with CAS. Thus, our findings reinforce that FOXP2 provides a valuable entry point for examining the neurobiological bases of speech disorder.

Neurocognitive development in isolated Robin sequence treated with the Tuebingen palatal plate.

OBJECTIVES: We aimed to determine the neurocognitive development of cleft palate patients with and without Robin sequence (RS). MATERIALS AND METHODS: Children with isolated RS with cleft palate and children with cleft palate only (CPO) were contacted at the age of 5-6 years. All RS children had undergone initial polygraphic sleep study (PG) with a mixed-obstructive apnea index (MOAI) of ≥ 3/h and were consequently treated with the Tuebingen palatal plate. A standardized clinical examination as well as a neuropediatric and neuropsychological examination included the Wechsler Pre-school and Primary Scale of Intelligence (WPPSI-III), Kaufman Assessment Battery for Children (K-ABC), and an assessment of developmental milestones. RESULTS: In total, 44 children (22RS, 22CPO) were included. RS children were younger at study (70.5 ± 7.3 and 75.2 ± 7.5 months; P = .035). Both groups achieved the evaluated milestones within the normed time frame. WPPSI-III and K-ABC results showed no group differences. Mean values for Verbal IQ (101.8 ± 11.1 vs. 97.1 ± 15.7), Performance IQ (102.9 ± 12.1 vs. 99.6 ± 14.5), Processing Speed Quotient (98.9 ± 15.6 vs. 94.5 ± 15.7), Full-Scale IQ (103.2 ± 12.1 vs. 98.4 ± 15.3), and Sequential Processing Scale (102.1 ± 13.1 vs. 94.2 ± 17.3) were within the reference range (IQ 85-115) for RS and CPO children, respectively, indicating average performance of both groups. CONCLUSION: No neurocognitive, physical, or mental impairments were detected suggesting that RS children having upper airway obstruction (UAO) treated early and effectively may use their potential for an age-appropriate neurocognitive development. CLINICAL RELEVANCE: Tuebingen palatal plate treatment successfully releases UAO. Thus, isolated RS does not necessarily result in developmental delay or an impaired neurocognitive outcome. TRIAL REGISTRATION: Deutsches Register Klinischer Studien, DRKS00006831, https://www.drks.de/drks_web/.