• Journal of Genetic Medicine
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• v.17 no.2
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• pp.92-96
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• 2020

Hypotonia, Ataxia, and Delayed Development Syndrome (HADDS) is an autosomal-dominant, extremely rare neurodevelopmental disorder caused by the heterozygous EBF3 gene mutation. EBF3 is located on chromosome 10q26.3 and acts as a transcription factor that regulates neurogenesis and differentiation. This syndrome is characterized by dysmorphism, cerebellar hypoplasia, urogenital anomaly, hypotonia, ataxia, intellectual deficit, and speech delay. The current report describes a 3-year-old Korean male carrying a de novo EBF3 mutation, c.589A>G (p.Asn197Asp), which was identified by whole exome sequencing. He manifested facial dysmorphism, hypotonia, strabismus, vermis hypoplasia, and urogenital anomalies, including vesicoureteral reflux, cryptorchidism, and areflexic bladder. This is the first report of a case of HADDS cause by an EBF3 mutation in the Korean population.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.2
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• pp.155-159
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• 2022

Cohen syndrome is a rare genetic disorder associated with mutations in the VPS13B gene. Individuals with this disorder present with diverse clinical manifestations, including muscle hypotonia, intellectual disabilities, and typical facial characteristics, such as prominent upper central incisors and micrognathia. General anesthesia was administered to a 23-year-old man with Cohen syndrome. Although we observed prominent upper central incisors, an overjet of 10 mm, micrognathia, and thyromental distance of 4 cm, hypotonia was not observed in the patient. Intubation was rendered difficult when performing a direct laryngoscopy. However, smooth intubation was achieved using a video laryngoscope. The patient's train of four (TOF) count remained zero close to 60 min after rocuronium administration, suggesting that the drug's muscle-relaxant effect may have been prolonged. A TOF ratio of 0.79 was confirmed 130 min after rocuronium administration, and a TOF ratio of 1.0 was confirmed after administration of 150 mg of sugammadex. The patient's respiration remained stable after extubation, and no recurarization of muscle relaxation was observed. As demonstrated in this case report, it is important to closely monitor recovery from muscle relaxation and prepare multiple techniques for airway management in general anesthesia management of patients with Cohen syndrome.

• Clinical and Experimental Pediatrics
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• v.56 no.3
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• pp.139-142
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• 2013

X-linked recessive myotubular myopathy (XLMTM) is a severe congenital muscle disorder caused by mutations in the MTM1 gene and characterized by severe hypotonia and generalized muscle weakness in affected males. It is generally a fatal disorder during the neonatal period and early infancy. The diagnosis is based on typical histopathological findings on muscle biopsy, combined with suggestive clinical features. We experienced a case of a newborn who required intubation and ventilator care because of profound hypotonia and respiratory difficulty. The preliminary diagnosis at the time of request for retrieval was hypoxic ischemic encephalopathy, but the infant was clinically reevaluated for generalized weakness and muscle atrophy. Muscle biopsies showed variability in fiber size and centrally located nuclei in nearly all the fibers. We detected an MTM1 gene mutation of c.1261-1C>A in the intron 10 region, and diagnosed the neonate with myotubular myopathy. The same mutation was detected in his mother.

• Journal of the Korean Child Neurology Society
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• v.26 no.4
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• pp.189-196
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• 2018

Purpose: Floppy infants or congenital hypotonia indicates decreased muscle tone in infants secondary to abnormalities of the central or the peripheral nervous system, or both. Previous literature classified its causes as those attributable to a central vs. peripheral origin; however, recent studies have introduced a newer classification describing a combined origin. We invenstigated floppy infants by applying the new etiological classification and reviewed the most common etiologies based on the age of presentation. We additionally reviewed the clinical characteristics, diagnoses, and the developmental outcomes in these infants. Methods: We retrospectively reviewed the electronic medical charts and recruited 116 infants diagnosed with floppy infant syndrome between January 2005 and December 2016 at Severance Children's Hospital. Among these infants, 66 with a confirmed diagnosis were reviewed for the etiological classification. Information regarding developmental outcomes was obtained via phone interviews with the infants' families. Results: Based on the new etiological classification, among 69 infants with a confirmed diagnosis, in 40 (34.5%) this syndrome was of central origin, in 19 (16.4%) of peripheral origin, and in 10 (8.6%) of combined origin. Prader-Willi syndrome, myotonic dystrophy, and spinal muscular atrophy were the most common disorders observed and combined hypotonia showed the poorest developmental outcome. Conclusion: The study states the importance of proper evaluation of etiological diagnosis and optimal intervention for developmental prognosis. The introduction of a new etiological group of combined hypotonia especially emphasizes regular monitoring and timely rehabilitative intervention in patients for the better quality of life in them as well as their caregivers.

• Clinical and Experimental Pediatrics
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• v.51 no.12
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• pp.1295-1299
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• 2008

Inherited muscle diseases are heterogeneous with varying genetic etiologies and present with common symptoms and signs, including weakness, motor developmental delay, and hypotonia. To diagnose these various diseases, a meticulous family and clinical history, physical and neurological examinations, laboratory findings with electromyography, muscle biopsy, and genetic testing are needed. Here, I review several inherited muscle diseases, with a focus on muscular dystrophy in children and its genetics and general management.

• Clinical and Experimental Pediatrics
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• v.58 no.8
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• pp.313-316
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• 2015

Interstitial deletions involving the chromosome band 15q22q24 are very rare and only nine cases have been previously reported. Here, we report on a 12-day-old patient with a de novo 15q22q23 interstitial deletion. He was born by elective cesarean section with a birth weight of 3,120 g at 41.3-week gestation. He presented with hypotonia, sensory and neural hearing loss, dysmorphism with frontal bossing, flat nasal bridge, microretrognathia with normal palate and uvula, thin upper lip in an inverted V-shape, a midline sacral dimple, severe calcanovalgus at admission, and severe global developmental delay at 18 months of age. Fluorescence in situ hybridization findings confirmed that the deleted regions contained at least 15q22. The chromosome analysis revealed a karyotype of 46,XY,del(15) (q22q23). Parental chromosome analysis was performed and results were normal. After reviewing the limited literature on interstitial 15q deletions, we believe that the presented case is the first description of mapping of an interstitial deletion involving the chromosome 15q22q23 segment in Korea. This report adds to the knowledge of the clinical phenotype associated with the 15q22q23 deletion.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.459-466
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• 2011

The purpose of this study was to analyze of obstacle gait using spatio-temporal and foot pressure variables in children with autism. Fifteen children with autism and fifteen age-matched controls participated in the study. Spatio-temporal and foot pressure variables was investigated using GAITRite pressure sensor system. Each footprint was divided into 12 equal trapezoids and after that the hindfoot, midfoot and forefoot analysis was developed. Independent t-test was applied to compare the gait variables between the groups. The results showed that the autism group were significantly decreased in velocity, cadence, cycle and swing time compared to the control group. The autism group were significantly increased in step width and toe out angle compared to the control group. The autism group were significantly increased at midfoot and forefoot of lateral part of footprint and forefoot of medial part of footprint in the peak time compared to the control group. The autism group were significantly increased at midfoot and hindfoot in $P^*t$, at midfoot in active area, and at hindfoot in peak pressure compared to the control group. In conclusion, the children with autism showed abnormal obstacle gait characteristics due to muscle hypotonia, muscle rigidity, akinesia, bradykinesia and postural control impairments.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.5 no.1
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• pp.18-22
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• 2005

Pompe disease is a genetic disorder caused by a deficiency of acid ${\alpha}$-glucosidase (GAA). This enzyme defect results in lysosomal glycogen accumulation in multiple tissues and cell types, with cardiac, skeletal, and smooth muscle cells the most seriously affected. Infantile-onset Pompe disease is uniformly lethal. Affected infants present in the first few months of life with hypotonia, generalized muscle weakness, and a hypertrophic cardiomyopathy, followed by death from cardiorespiratory failure or respiratory infection, usually by 1 year of age. Late-onset forms is characterized by a lack of severe cardiac involvement and a less severe short-term prognosis. Enzyme replacement therapy for Pompe disease is intended to address directly the underlying metabolic defect via intravenous infusions of recombinant human GAA to provide the missing enzyme. We experienced one case of Pompe disease in 3-years old boy that has improved his exercise ability and cardiac function after GAA enzyme replacement therapy.

• Clinical and Experimental Pediatrics
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• v.57 no.3
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• pp.149-152
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• 2014

Congenital muscular dystrophy type 1A (MDC1A) is an autosomal recessive disorder characterized by hypotonia, elevated serum creatine kinase level, delayed motor milestones, white matter changes observed by brain magnetic resonance imaging, and normal intelligence. A mutation in the laminin ${\alpha}2$ (LAMA2) gene, located at 6q22-23, is a genetic cause of MDC1A. Patients have merosin (laminin ${\alpha}2$)-deficient skeletal muscles. However, the degree of merosin expression ranges from total absence to partial reduction. Patients with residual merosin expression have more variable and milder phenotypes than those with absolute merosin deficiency. We observed a Korean girl with MDC1A with residual merosin expression. Clinical presentation of this patient was typical except for late onset of the disease and external capsule involvement. Immunohistochemical staining of muscle fibers including merosin, is important to evaluate patients with hypotonia, delayed motor development, and abnormal white matter changes.

• The Journal of Pediatrics of Korean Medicine
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• v.14 no.1
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• pp.197-204
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• 2000

Neuromuscular disorders are common causes of weakness and hypotonia in the infantile period and in childhood. Accurate diagnosis of specific neuromuscular disorders depends first on identification of which aspect of the peripheral neuromuscular system is affected-the motor neuron in the spinal cord, the nerve root or peripheral nerve, the neuromuscular junction, or the muscle-and then on the determination of the etiology and specific clinical entity. Spinal muscular atrophy(SMA) is the most common autosomal-recessive genetic disorder lethal to infants. The three major childhood-onset forms of SMA are now usually called type I, type II and typeⅢ. Progression of the disease is due to loss of anterior horn cells, thought to be caused by apoptosis. Diagnosis is based on the course of the illness, as well as certain changes seen on nerve and muscle biopsy and electrodiagnostic studies. More recently, our understanding of the genetics of this disorder has provided a noninvasive approach to diagnosis. We report on a 3-year-old male patient with spinal muscular atrophy type II. He had progressive muscular weakness since 18 months of age. The upper arms were slightly, and the thighs moderately atrophic. There was muscle weakness of both the upper and lower limbs, being more proximal in distribution. Electromyogram revealed a neurogenic pattern.