• Journal of The Korean Society of Inherited Metabolic disease
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• v.19 no.1
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• pp.20-25
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• 2019

Very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency (OMIM#201475) is an autosomal recessively inherited metabolic disorder of mitochondrial long-chain fatty acid oxidation. The clinical features of VLCAD deficiency is classified by three clinical forms according to the severity. Here, we report a case of later-onset episodic myopathic form of VLCAD deficiency whose diagnosis was confirmed by plasma acylcarnitine analysis and" multigene panel multigene panel sequencing. A 34-year old female patient visited genetics clinic for genetic evaluation for history of recurrent myopathy with intermittent rhabdomyolysis. She suffered first episode of rhabdomyolysis with acute renal failure requiring hemodialysis at twelve years old. After then, she suffered several times of recurrent rhabdomyolysis provoked by prolonged exercise or fasting. Physical and neurologic exam was normal. Serum AST/ALT and creatinine kinase (CK) levels were mildly elevated. However, according to her previous medical records, her AST/ALT, CK were highly elevated when she had rhabdomyolysis. In suspicion of fatty acid oxidation disorder, multigene panel sequencing and plasma acylcarnitine analysis were performed in non-fasting, asymptomatic condition for the differential diagnosis. Plasma acylcarnitine analysis revealed elevated levels of C14:1 ($1.453{\mu}mol/L$; reference, 0.044-0.285), and C14:2 ($0.323{\mu}mol/L$; 0.032-0.301) and upper normal level of C14 ($0.841{\mu}mol/L$; 0.065 -0.920). Two heterozygous mutation in ACADVL were detected by multigene panel sequencing and confirmed by Sanger sequencing: c.[1202G>A(;) 1349G>A] (p.[(Ser 401Asn)(;)(Arg450His)]). Diagnosis of VLCAD deficiency was confirmed and frequent meal with low-fat diet was educated for preventing acute metabolic derangement. Fatty acid oxidation disorders have diagnostic challenges due to their intermittent clinical and laboratorial presentations, especially in milder late-onset forms. We suggest that multigene panel sequencing could be a useful diagnostic tool for the genetically and clinically heterogeneous fatty acid oxidation disorders.

• Journal of Genetic Medicine
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• v.19 no.1
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• pp.27-31
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• 2022

X-linked dominant hypophosphatemic rickets are the most common form of familial hypophosphatemic rickets resulting from hypophosphatemia caused by renal phosphate wasting, which in turn is a result of loss-of-function mutations in PHEX. Herein, we report a 39-year-old female with short stature and skeletal deformities and 12-month-old asymptomatic daughter. The female has a history of multiple surgical treatments because of lower limb deformities. Her biochemical findings revealed low serum phosphorus levels with elevated serum alkaline phosphatase activity and normal serum calcium levels, suggesting presence of hypophosphatemic rickets. To identify the molecular causes, we used a multigene testing panel and found a mutation, c.667dup (p.Asp223GlyfsTer15), in PHEX gene. To the best of our knowledge, this is a novel mutation. A heterozygous form of the same variant was detected in daughter, who showed no typical symptoms such as bow legs, frontal bossing, or waddling gate, but presented early signs of impaired mineralization in both X-ray and biochemical findings. The daughter was initiated onto early medical treatment with oral phosphate supplementation and an active vitamin D analog. Because the daughter was genetically diagnosed based on a family history before the onset of symptoms, appropriate medical management was possible from early infancy.