1.Intellectual Disability and Borderline Intellectual Functioning: An Updated Pediatric Neurology Perspective
Youngkyu SHIM ; Dong Hwa YANG ; Baik-Lin EUN ; Jung Hye BYEON
Annals of Child Neurology 2026;34(1):13-24
Intellectual disability (ID) affects 1%–3% of the population, while borderline intellectual functioning (BIF) affects 13%–14% of individuals, together representing a substantial burden in pediatric neurology. This review synthesizes current evidence on diagnostic frameworks, genomic advances, and targeted therapeutics relevant to pediatric practice. We reviewed recent literature focusing on Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) and International Classification of Diseases, 11th Revision (ICD-11) updates, genomic diagnostic innovations, and emerging therapies identified through PubMed and clinical trial registries (2019–2024). Diagnostic frameworks now emphasize adaptive functioning rather than intelligence quotient (IQ)-based classifications, with severity defined by required support levels rather than cognitive scores. Genomic testing has progressed from chromosomal microarray (10%–20% yield) to trio whole-exome sequencing (30%–45% yield), with professional guidelines endorsing genome-first approaches as first-line testing. Common comorbidities require systematic management, including autism spectrum disorder (15%–20%), attention-deficit/hyperactivity disorder (20%), epilepsy (20%–30% in moderate-to-severe cases), and mental health disorders. Traditional management continues to prioritize early intervention, educational support, and comprehensive medical care, while emerging targeted therapies show clinical benefit, including U.S. Food and Drug Administration-approved trofinetide for Rett syndrome and investigational antisense therapies for Angelman syndrome. Contemporary ID management demands genome-first diagnostic strategies, structured comorbidity assessment, and integration of targeted therapeutics. The BIF population requires formal diagnostic recognition and broader service eligibility. Optimal outcomes depend on collaboration among pediatric neurologists, geneticists, and developmental specialists through precision-medicine–based approaches.
2.Cerebral Visual Impairment: Current Concepts, Clinical Assessment, and Management
Jung Hye BYEON ; Youngkyu SHIM ; Han Na JANG ; Baik-Lin EUN ; Donghwa YANG
Annals of Child Neurology 2026;34(1):49-55
Cerebral visual impairment (CVI) is recognized as the most common cause of visual impairment in children in high-income countries. It refers to a heterogeneous group of visual processing deficits of cerebral origin that cannot be explained by ocular pathology alone. Major risk factors include prematurity, perinatal brain injury, and structural abnormalities of the developing brain. The terminology has shifted from cortical to CVI to reflect involvement of the entire visual network, including both primary and associative pathways. The term ‘cerebral visual disorders’ has been proposed to describe a broader range of visuoperceptual dysfunction. Clinically, CVI is characterized by inconsistent visual behaviors, including impaired visual attention, difficulty processing complex visual scenes, and delayed visual responses, often despite relatively preserved visual acuity. Diagnosis is clinical and multidisciplinary, requiring exclusion of ocular causes and assessment of functional vision. Neuroimaging may support etiological classification, but is not definitive for diagnosis. Early identification is important, as timely intervention is associated with improved visual and developmental outcomes. Parent-reported questionnaires serve as useful screening tools in early childhood, and the Korean parental questionnaire for children younger than 72 months provides an age-appropriate example. In this mini-review, management is framed around visual habilitation and environmental modification tailored to the child’s visual profile. Although prognosis varies, early recognition and targeted support can improve functional vision and overall quality of life.
3.Developmental Language Disorder: Current Understanding, Clinical Implications, and Future Directions
Youngkyu SHIM ; Dong Hwa YANG ; Baik-Lin EUN ; Jung Hye BYEON
Annals of Child Neurology 2026;34(1):5-12
Developmental language disorder (DLD) is a common yet under-recognized neurodevelopmental condition characterized by persistent difficulties in acquiring and using language that cannot be explained by hearing loss, intellectual disability, or known neurological injury. Children with DLD exhibit deficits across phonology, morphology, syntax, semantics, and pragmatics, which have downstream effects on literacy and academic attainment. DLD frequently co-occurs with attention-deficit/hyperactivity disorder, dyslexia, and speech sound disorders. Early identification requires attention beyond vocabulary counts to subtler markers such as syntactic comprehension, working memory, and processing speed. Converging genetic and neurobiological evidence suggests a polygenic risk profile and subtle alterations in brain connectivity. Cross-linguistic research is essential for distinguishing universal from language-specific markers and refining culturally appropriate standardized assessments. Because DLD is heterogeneous and multidimensional, it demands early detection, evidence-based intervention, and robust policy support that account for linguistic and cultural diversity to improve long-term outcomes.
4.Clinical Spectrum of Myelin Oligodendrocyte Glycoprotein-Immunoglobulin G-Associated Disease in Korean Children
Il Han YOO ; WooJoong KIM ; Youngkyu SHIM ; Sun Ah CHOI ; Soo Yeon KIM ; Hunmin KIM ; Byung Chan LIM ; Hee HWANG ; Jieun CHOI ; Ki Joong KIM ; Yeseul KIM ; Jae-Won HYUN ; Su-Hyun KIM ; Kyungho CHOI ; Ho Jin KIM ; Jong-Hee CHAE
Journal of Clinical Neurology 2020;16(3):461-469
Background:
and Purpose: The myelin oligodendrocyte glycoprotein (MOG) antibody is detected at a high rate in childhood acquired demyelinating syndrome (ADS). This study aimed to determine the diagnostic value of the MOG antibody in ADS and the spectrum of MOGantibody-positive demyelinating diseases in children.
Methods:
This study included 128 patients diagnosed with ADS (n=94) or unexplained encephalitis (n=34). The MOG antibody in serum was tested using an in-house live-cell-based immunofluorescence assay.
Results:
The MOG antibody was detected in 48 patients (46 ADS patients and 2 encephalitis patients, comprising 23 males and 25 females). Acute disseminated encephalomyelitis (ADEM) (35.4%) was the most-common diagnosis, followed by the unclassified form (17.4%), isolated optic neuritis (ON) (15.2%), neuromyelitis optica spectrum disorder (13.0%), multiple sclerosis (MS) (10.8%), other clinically isolated syndromes [monophasic event except ADEM, isolated ON, or transverse myelitis (TM)] (8.7%), and unexplained encephalitis (4.3%). At the initial presentation, 35 out of the 46 patients with ADS had brain lesions detected in magnetic resonance imaging, and 54% of these 35 patients had encephalopathy. Nine of the 11 patients without brain lesions exhibited only ON. Thirty-nine percent of the patients experienced a multiphasic event during the mean follow-up period of 34.9 months (range 1.4–169.0 months). Encephalopathy at the initial presentation was frequently confirmed in the monophasic group (p= 0.011).
Conclusions
MOG antibodies were identified in all pediatric ADS phenotypes except for monophasic TM. Therefore, the MOG antibody test is recommended for all pediatric patients with ADS, especially before a diagnosis of MS and for patients without a clear diagnosis.
5.A familial case of limb-girdle muscular dystrophy with CAV3 mutation
Seungbok LEE ; Sesong JANG ; Youngkyu SHIM ; Woo Joong KIM ; Soo Yeon KIM ; Anna CHO ; Hunmin KIM ; Jong Il KIM ; Byung Chan LIM ; Hee HWANG ; Jieun CHOI ; Ki Joong KIM ; Jong Hee CHAE
Journal of Genetic Medicine 2019;16(2):67-70
Limb-girdle muscular dystrophy (LGMD) is a group of muscular dystrophies that has extremely heterogeneous clinical features and genetic background. The caveolin-3 gene (CAV3) is one of the causative genes. LGMD appears as a clinical continuum, from isolated skeletal muscle involvement to long QT syndrome. Here we report two patients without apparent muscle weakness in a family with CAV3 mutation.A 7-month-old Korean boy visited our muscle clinic because of an incidental finding of elevated serum creatine kinase (CK) concentration (680 IU/L, reference range, 20-270 IU/L) without clinical symptoms. The patient was born after an uneventful pregnancy and showed normal developmental milestones. He developed pseudohypertrophy of his calf muscle during the follow-up. We obtained a muscle biopsy at age 14 months, which showed size variations and degenerating/regenerating myofibers with endomysial fibrosis and immunohistochemical evidence of normal dystrophin. Under the impression of LGMD, we performed target panel sequencing and identified a heterozygous in-frame mutation of CAV3, c.307_312delGTGGTG (p.Val103_Val104del). Immunohistochemical staining of muscle indicated complete loss of caveolin-3 compared with normal control muscle, which supported the variant's pathogenicity. We performed segregation analysis and found that the patient's mother had the same variant with elevated serum CK level (972 IU/L).We report on autosomal dominant familial caveolinopathy caused by a pathogenic variant in CAV3, which was asymptomatic until the fourth decade. This case highlights the utility of next generation sequencing in the diagnosis of muscular dystrophies and the additive role of muscle biopsy to confirm the variants.
6.Epstein-Barr Virus Infection associated Transverse Myelitis with Brain Involvement in an Immunosuppressed Patient: A Case Report.
Youngkyu SHIM ; Hunmin KIM ; Hee HWANG ; Jong Hee CHAE ; Jieun CHOI ; Ki Joong KIM ; Ki Joong LIM
Journal of the Korean Child Neurology Society 2017;25(4):277-280
A 19-year-old girl with immunosuppressive agents of tacrolimus and mychophenolate mofetil following liver transplantation due to glycogen storage disease visited hospital due to lower extremity motor weakness and blurred vision. Motor power was checked as grade II in the upper extremities and grade 0 in the lower extremities with absence of deep tendon reflexes and anal sphincter dysfunction. The magnetic resonance imaging (MRI) showed increased T2 high signal intensity lesions from C4 to L2 level of spinal cord, cerebral cortex, and the left optic nerve. The cerebrospinal fluid (CSF) analysis showed pleocytosis. Epstein-Barr virus (EBV) deoxyribonucleic acid (DNA) was detected as 5,954 copies/mL in CSF whereas all other microbiologic tests were negative. Anti-aquaporin 4 antibody and oligoclonal band were not detected. Intravenous immunoglobulin, methylprednisolone pulse therapy and 3-week course of acyclovir were administered. Although motor power in the upper extremities recovered to grade V, motor power in the lower extremities did not show any improvement. The EBV viral load was not detected in the follow-up CSF examination. EBV infection in an immune-compromised patient could cause extensive demyelinating diseases in central nervous system and result in severe disability.
Acyclovir
;
Anal Canal
;
Brain*
;
Central Nervous System
;
Cerebral Cortex
;
Cerebrospinal Fluid
;
Demyelinating Diseases
;
DNA
;
Epstein-Barr Virus Infections
;
Female
;
Follow-Up Studies
;
Glycogen Storage Disease
;
Herpesvirus 4, Human*
;
Humans
;
Immunocompromised Host
;
Immunoglobulins
;
Immunosuppressive Agents
;
Leukocytosis
;
Liver Transplantation
;
Lower Extremity
;
Magnetic Resonance Imaging
;
Methylprednisolone
;
Myelitis, Transverse*
;
Optic Nerve
;
Reflex, Stretch
;
Spinal Cord
;
Tacrolimus
;
Upper Extremity
;
Viral Load
;
Young Adult
7.Clinical and Radiologic Features of Pediatric Cerebral Venous Thrombosis in Korea.
Youngkyu SHIM ; Hunmin KIM ; Hee HWANG ; Jong Hee CHAE ; Jieun CHOI ; Ki Joong KIM ; Byung Chan LIM
Journal of the Korean Child Neurology Society 2017;25(4):234-239
PURPOSE: Cerebral venous thrombosis (CVT) is a rare cause of pediatric stroke. Our goal was to describe the clinical CVT features among pediatric patients presenting at a tertiary referral center. METHODS: Patient data was retrospectively collected from the charts of all pediatric patients (newborn to 18 years old) who were diagnosed with CVT at Seoul National University Children's Hospital between 2000 and 2016. Magnetic resonance imaging or venography was conducted for diagnostic confirmation. Modified Rankin Scale (mRS) was used to evaluate neurologic outcome. RESULTS: Twenty patients were diagnosed with CVT during the study period (16 male, 4 female). Median age was 4 years. The most common risk factor was systemic infection (6/20, 30.0%). Twelve patients initially presented with headache or vomiting (12/20, 60.0%). Seizure was in only 3 patients within 48 hours of symptom onset; however, as the clinical course progressed, seizure was the symptom that most frequently led to brain imaging (12/20, 60.0%). Thrombosis in the superior sagittal sinus was frequently associated with intracranial hemorrhage (4/11, 36.4%) and clinical seizure (9/11, 81.8%). Anticoagulation and/or antiplatelet agents were used in 16 patients (16/20, 80%). At the 3-month follow-up, 14 patients (14/20, 70%) had an mRS of 0 or 1, showing that most of these patients had no neurologic impairment. CONCLUSION: Seizure and signs of increased intracranial pressure are the most common manifestation of pediatric CVT. However, clinical features are diverse and include age at symptom onset and underlying risk factors. Despite diagnostic delay, neurologic outcome is favorable in most patients.
Follow-Up Studies
;
Headache
;
Humans
;
Intracranial Hemorrhages
;
Intracranial Pressure
;
Korea*
;
Magnetic Resonance Imaging
;
Male
;
Neuroimaging
;
Pediatrics
;
Phlebography
;
Platelet Aggregation Inhibitors
;
Retrospective Studies
;
Risk Factors
;
Seizures
;
Seoul
;
Stroke
;
Superior Sagittal Sinus
;
Tertiary Care Centers
;
Thrombosis
;
Venous Thrombosis*
;
Vomiting

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