MOLECULAR BASIS OF LANGUAGE DEVELOPMENT AND ASSOCIATED DISORDERS

Patients Inclusion Criteria: * Eligible families included at least one child over five years old with a formal diagnosis of severe and isolated DLD according to Phase 2 CATALISE criteria . Patients have undergone age-appropriate speech, language and reading evaluations by a speech-language physician and cognitive evaluations by a neuropsychologist, as well as evaluation by a pediatric neurologist to identify co-occurring developmental disorders (ADHD, ASD…) and a medical geneticist for known genetic disorders and genetic testing recommendations. All children included received appropriate speech therapy for at least one year, with a progress report indicating the persistence of language difficulties. Exclusion Criteria: * Cognitive impairment with non-verbal intellectual quotient (IQ) below 2 SD assessed with the Wechsler Preschool and Primary Scale of Intelligence (WPPSI), or the Wechsler Intelligence Scale for Children (WISC-IV or V) according to the age-appropriateness, ASD, moderate to severe hearing loss, orofacial structural abnormalities, known neurological or genetic disorders at the initial assessment. None of the patients met the diagnostic criteria for CAS according to the ASHA (American Speech-Language-Hearing Association, 2007. Childhood apraxia of speech www.asha.org/policy).