A developmental language disorder (DLD) is a neurobiological condition characterized by impaired language development despite adequate linguistic input and normal intelligence. The role of monogenic causes in the pathogenesis of DLD is largely unknown and diagnostic genetic testing is rarely offered. This study assessed the diagnostic yield of genome sequencing in severe DLD and investigated the underlying genetic foundations. We designed a prospective cohort study involving trio-based genome sequencing in 25 individuals (aged 3-25 years) with severe DLD, no intellectual disability (non-verbal IQ ≥ 70), no autism spectrum disorder diagnosis and no first-degree family history of DLD or neurodevelopmental disorders. (Likely) pathogenic variants were found in nine of 25 individuals, reflecting a molecular diagnostic yield of 36%. The genetic causes were diverse and involved seven autosomal dominant disorders, one autosomal recessive disorder, and one sex chromosome aneuploidy. In seven individuals, the disease-causing variant occurred de novo. All identified (likely) pathogenic variants were located in genes or loci that have been previously implicated in neurodevelopmental disorders with variable clinical presentations. Importantly, the genetic diagnosis provided actionable insights for counselling and clinical follow-up for all nine individuals. This study reveals a high prevalence of rare (mainly de novo) genetic variants in individuals with severe and sporadic DLD, and demonstrates extensive molecular overlap with other neurodevelopmental disorders. Our results support the implementation of routine trio-based genetic testing in individuals with severe and sporadic DLD.
Milou G. P. Kennis, Leenke van Haaften, K. van Hulst et al.· European Journal of Human Ge...· 0 citations
This report describes the diagnostic and treatment course of an adult woman with the ultra-rare Au-Kline syndrome (AUKS). Since the age of 32 years, when the syndrome was yet undiagnosed, the patient suffered from behavioral decline coinciding with changes in living conditions. At the age of 38, following a bladder infection, she presented with a delirium for which antipsychotic medication was started. The delirium resolved but, while the medication was continued, the pre-existing behavioral symptoms persisted. Clinicpal genetic evaluation revealed a history of congenital hypotonia, developmental delay, and multiple (craniofacial) dysmorphisms. Subsequent trio-based genetic testing demonstrated a novel pathogenic variant in the HNRNPK gene, causative for AUKS. Clinical neuropsychological assessment showed moderate intellectual disability, slow information processing speed, restricted verbal expression, and limited comprehension. Registration of sensory information was severely hampered and there was difficulty in self-modulating the sensory information to be processed. Contextual adaptations and individual psychomotor therapy were then implemented to optimize sensory and motor information processing, to promote daily functioning, and reduce behavioral decline. These interventions, along with the long-term psychotropic medication, had beneficial effects on her functioning, which subsequently returned to near premorbid levels by the age of 45. Overall, this case underscores that the genetic and neuropsychological identification of a neurodevelopmental disorder, together with the integration of tailored psychomotor interventions and contextual adaptations, can improve psychiatric management and daily functioning, and mitigate behavioral decline in adulthood, even following a prolonged diagnostic delay.
A. Bos-Roubos, Rosalie te Brinke, A. Kattentidt-Mouravieva et al.· Frontiers in Psychiatry· 0 citations
An integrative study combining Mendelian genetics, clinical and association studies, and animal and molecular modeling supports variants in ELAVL2 as a cause of a neurodevelopmental disorder, with haploinsufficiency as the disease mechanism, and identifies crucial roles of ELAVL2 in neuronal function, cognition, and behavior.
Marina Boon, Meghan R. Mulligan, Jolijn J A Verseput et al.· American Journal of Human Ge...· 0 citations