UNASSIGNED: GNAO1 variants have been found to be associated with epileptic encephalopathies, developmental delays (DDs), and movement disorders (MDs). Therapies for patients with GNAO1 variants vary. However, treatments for GNAO1-related diseases are still in their infancy. Previous reports suggest that few pharmacological treatments are effective for patients with GNAO1 variant-related MDs. Deep brain stimulation (DBS) treatment appears to be effective, however surgical procedures and equipment failures pose risks to the patients. Effectiveness for oxcarbazepine (OXC) in GNAO1 variant-related MDs is first reported in our study, and it expand the effective drugs for MD treatment.
UNASSIGNED: We report the case of a 5-year-old male patient with a MD, who suffered from hypotonia and refractory choreoathetosis. The patient was found to have a DD and an intellectual disability. A de-novo variant of the GNAO1 gene (NM_138736: exom6: c.709G>A [p. Glu237Lys]) was identified by whole exome sequencing (WES) when he was 8 months old. The patient visited our hospital at the age of 4 years and 3 months because of fever and recurrent convulsions. Electroencephalogram (EEG) results show abnormal spikes, and magnetic resonance imaging (MRI) showed the enlargement of the lateral ventricles. The administration of tiapride hydrochloride, phenobarbital, midazolam, and hormones had no effect. OXC treatment was then initiated. No MD behaviors, such as rigidity and twisting of the limbs and trunk, or chorea, were observed after 10 days OXC treatment. Eventually, incremental doses of OXC were effective, and our patient achieved good control of his MD.
UNASSIGNED: We are the first to demonstrate the role of OXC in alleviating MDs associated with GNAO1 mutations. This report provides a novel possibility for the clinical treatment of this rare disease. To manage MDs associated with GNAO1 mutations, we recommend that OXC treatment be attempted before invasive surgical therapy.

Background: Genetic causes in most affected children with intellectual disability and/or development delay remain unknown. Methods: To identify potential variants responsible for these disorders, we recruited 161 affected families and performed whole-exome sequencing and associated bioinformatics analysis. Results: In the present study, we report the identification of variants in the ALG13 gene in two of the families. In family 1, a known pathogenic missense variant (c.23T > C; p.V8A) of ALG13 was identified in a boy and his mother. In family 2, a novel missense variant (c.862C > G; p.L288V) of the same gene was identified in the affected boy and his phenotypically normal mother. Genotype-phenotype correlation analysis by comparing reported 28 different variants (HGMD) showed that three major phenotypes, including various seizures/epilepsy, intellectual disability, and development delay (such as growth, speech, motor, etc.), are present in most affected individuals. However, other phenotypes, such as strabismus and absence of seizure in our second patient, are not reported if any, which may represent a unique case of X-linked recessive nonsyndromic disorder caused by a mutation in ALG13. Conclusion: We identified two missense variants in ALG13 in a cohort of 161 families with affected individuals diagnosed as intellectual disability and/or development delay. A novel c.862C > G mutation may represent a case of X-linked recessive.

The 15q11.2 breakpoint (BP) 1-BP2 deletion syndrome is emerging as the most frequent pathogenic copy number variation in humans related to neurodevelopmental diseases, with changes in cognition, behavior, and brain morphology. Previous publications have reported that patients with 15q11.2 BP1-BP2 deletion showed intellectual disability (ID), speech impairment, developmental delay (DD), and/or behavioral problems. We describe three new cases, aged 3 or 6 years old and belonging to three unrelated Korean families, with a 350-kb 15q11.2 BP1-BP2 deletion of four highly conserved genes, namely, the TUBGCP5, CYFIP1, NIPA2, and NIPA1 genes. All of our cases presented with global DD and/or ID, and the severity ranged from mild to severe, but common facial dysmorphism and congenital malformations in previous reports were not characteristic. The 15q11.2 BP1-BP2 deletion was inherited from an unaffected parent in all cases. Our three cases, together with previous findings from the literature review, confirm some of the features earlier reported to be associated with 15q11.2 BP1-BP2 deletion and help to further delineate the phenotype associated with 15q11.2 deletion. Identification of more cases with 15q11.2 BP1-BP2 deletion will allow us to obtain a better understanding of the clinical phenotypes. Further explanation of the functions of the genes within the 15q11.2 BP1-BP2 region is required to resolve the pathogenic effects on neurodevelopment.

Chromosome 7q11.23 duplication syndrome is a well-recognised syndrome which involves the duplication of the same genes located in the Williams-Beuren critical region. However, in 2010, 4 patients were reported with a microduplication only in the HIP1 and YWHAG genes. We refer to this as a distal 7q11.23 duplication (dup7q11.23D). Here, we report the fifth de novo patient with dup7q11.23D, whose symptoms may be explained by YWHAG overexpression as was demonstrated recently in mice and obese patients. Finally, further studies will be necessary to delineate this emerging microduplication syndrome.