• 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.

• Childhood Kidney Diseases
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• v.9 no.2
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• pp.263-268
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• 2005

Epidermal nevus syndrome is a rare disease consisting of epidermal nevus and multisystem pathologic conditions associated with anomalies in the central nervous system, bone, eye, heart, vasculature and genito-urinary system. Hypophosphatemic rickets has been rarely observed in association with this syndrome. We report a case of hypophosphatemic rickets as sociated with epidermal nevus syndrome with review of the literature. (J Korean Soc Pediatr Nephrol 2005;9:263-268)

• Annals of Pediatric Endocrinology and Metabolism
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• v.23 no.4
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• pp.229-234
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• 2018

X-linked hypophosphatemic rickets is caused by loss-of-function mutations in PHEX, which encodes a phosphate-regulating endopeptidase homolog. We report a 26-year-old man with X-linked hypophosphatemic rickets who showed decreased serum phosphate accompanied by bilateral genu valgum and short stature. He had received medical treatment with vitamin D (alfacalcidol) and phosphate from the age of 3 to 20 years. He underwent surgery due to valgus deformity at the age of 14 and 15. Targeted gene panel sequencing for Mendelian genes identified a nonsense mutation in PHEX (c.589C>T; p.Gln197Ter) and a mosaic pattern where only 38% of sequence reads showed the variant allele. This mutation was not found in his mother, who had a normal phenotype. This is a case of a sporadic nonsense mutation in PHEX and up to date, this is the first case of a mosaic mutation in PHEX in Korea.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.108-112
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• 2000

Hypophosphatemic rickets is lack of reponse to physiologic doses of vitamin D, different from the vitamin D-dependent rickets. It is inherited in an X-linked dominant fashion. The prime features of this disorder are lowered serum phosphate levels, elevated serum alkaline phosphatase and normal serum calcium levels. The dental manifestation often include apical radiolucencies, abscess and fistulas of clinically sound teeth. Dental radiographs show ricketic bone trabeculations, abscent or abnormal lamina dura and abnormal cementum. This case which was diagnosed to hypophosphatemic rickets, showed multiple spontaneous periapical abscess and gingival fistula enlarged pulp chambers, extension of the pulp horns into the cusp tips and delayed eruption.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.23 no.1
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• pp.1-11
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• 2023

Inborn errors of metabolism encompass a wide variety of disorders, frequently affecting bone. This review presents a comprehensive retrospect on the primary involvement of bone in inborn errors of metabolism. Primary involvement of bone in inborn errors of metabolism includes entities that primarily affect the bone marrow, mineral component or cartilage. These include lysosomal storage disorders, hypophosphatasia, and hereditary hypophosphatemic rickets. In this review, we discuss the primary involvement of bone in inborn errors of metabolism (hypophosphatasia, X-linked hypophosphatemic rickets, Gaucher disease, and mucopolysaccharidoses) along with the therapeutic agents used in clinical settings, diagnostic strategies, and general management. With the development of disease-specific targeted therapies and supportive care, more number of patients with these disorders live longer and survive into adulthood. Moreover, skeletal symptoms have become a more prominent feature of these disorders. This makes the awareness of these skeletal symptoms more important.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.298-304
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• 2009

XLH (X-linked hypophosphatemic rickets) is a form of rickets which is resistant to the usual dose of vitamin D and inherited in a X-linked dominant manner. It is also known as vitamin D-resistant rickets or familial hypophosphatemic rickets. Here we report a 6-year-and-6-month-old female patient of XLH who is diagnosed with in SNUB. She was referred from local clinic for impaction of maxillary left permanent incisor and its treatment. She presents bowing deformities of the legs, short stature, enlargement of wrist and ankles and spontaneous dental abscesses of clinically sound teeth delayed eruption, taurodontism, delayed apical closure, enlarged pulp chambers, and absent or poorly defined lamina dura. The purpose of this case is to review the literatures of XLH and report the dental and medical characteristics of this patient.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.195-204
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• 2004

Purpose: Hypophosphatemic rickets is a hereditary disease, characterized by hypophosphatemia due to renal phosphate wasting, impaired renal production of 1,25-dihydroxyvitamin $D_3$, rachitic bone deformities and impaired growth. The purpose of this study is to provide clinical profiles of patients with hypophosphatemic rickets in our hospital. Methods: Between July 1983 and February 2004, 56 patients were diagnosed as having hypophosphatemic rickets. The medical records of these patients were reviewed retrospectively. Clinical manifestations, family histories, laboratory data, treatment outcomes were described. Results: Fifty six patients were enrolled in this study. The average age at symptom onset and diagnosis were 20 months and 5 years respectively. Fourteen patients had family histories. The main clinical manifestations were bow legs and short stature. There was a significant negative correlation between the ages and the height z-scores at the time of diagnosis(r=-0.47, P=0.005). Initial laboratory data showed normocalcemia, hypophosphatemia, elevated serum alkaline phosphatase, decreased tubular reabsorption of phosphate and a normal range of 1,25-dihydroxyvitamin $D_3$ Radiographic examinations of bone revealed fraying, widening and cupping of the metaphyseal ends. Treatment consisted of Joulie solution and vitamin D metabolites, and resulted in improved biochemical and radiographic findings. However, height z-scores remained essentially unchanged(P=0.224). Complications of treatment were frequently observed, including hyperparathyroidism, nephrocalcinosis, and hypercalciuria. Sixteen patients had corrective osteotomy and 4 of them underwent leg lengthening together. Conclusion: There was a gap of several years between the onset of symptoms and the diagnosis. Early treatment seems to be essential to growth. For the earlier treatment, the offsprings of affected parents should be followed up closely.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.1 no.1
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• pp.23-27
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• 2001

Fanconi-Bickel Syndrome (FBS) is a rare autosomal recessive disorder of carbohydrate metabolism recently demonstrated to be caused by mutations in the GLUT 2 gene for the glucose transporter protein 2 expressed in liver, pancreas, intestine, and kidney. This disease is characterized by hepatorenal glycogen accumulation, both fasting hypoglycemia as well as postprandial hyperglycemia and hyperglactosemia, and generalized proximal renal tubular dysfunctions. We report the first Korean patient with FBS diagnosed based on clinical manifestations and identification of a novel mutation in the GLUT 2 gene. She was initially diagnosed having a neonatal diabetes mellitus due to hyperglycemia and glycosuria at 3 days after birth. In addition, newborn screening for galactosemia revealed hypergalactosemia. Thereafter, she has been managed with lactose free milk, insulin therapy. However, she failed to grow and her liver has been progressively enlarging. Her liver functions were progressively deteriorated with increased prothrombin time. Liver biopsy done at age 9 months indicated micronodular cirrhosis with marked fatty changes. She succubmed to hepatic failiure with pneumonia at 10 months of age. Laboratory tests indicated she had generalized proximal renal tubular dysfuctions; renal tubular acidosis, hypophosphatemic rickets, and generalized aminoaciduria. Given aforementioned findings, the diagnosis of FBS was appreciated at age of 2 months. The DNA sequencing analysis of the GLUT 2 gene using her genomic DNA showed a novel mutation at 5th codon; Lysine5 Stop (K5X).

• Journal of The Korean Society of Inherited Metabolic disease
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• v.13 no.2
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• pp.120-125
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• 2013

Purpose: McCune-Albright syndrome (MAS) is caused by activating mutations in the GNAS gene, resulting in peripheral precocious puberty, caf$\acute{e}$-au-lait spots, and polyostotic fibrous dysplasia (POFD). The aim of the present study was to describe the diverse clinical and endocrine characteristics of patients with MAS. Methods: Seven patients with MAS were included in this study and medical charts were reviewed retrospectively for following parameters: patient's sex and age at diagnosis, POFD, ovarian cysts, and precocious puberty. Results: The mean age at diagnosis was $5.8{\pm}4.2$ years. One patient was male (14%) and the other six patients were female (86%). Peripheral precocious puberty was associated with 6 patients (86%). Five patients manifested premature menarche as early as 2 to 5 years of age. Letrozole was administered to 4 patients, tamoxifen to one patient and GnRH agonist to one patient. Five females developed ovarian cysts. Thyroid function tests were performed in all patients and one patient showed hyperthyroidism (14%) and has been treated with methimazole. One patient presented with pseudohypoparathyroisdism, phosphaturia, calciuria suggesting hypophosphatemic rickets. Six patients (86%) revealed POFD. One patient had symptoms of optic nerve compression and secondary esotropia and 2 patients had bone pain. Conclusion: This study described clinical characteristics and endocrine complications of patients with MAS. Careful physical examinations with history taking and serial endocrine function tests should be needed to detect complications such as endocrinologic hyperfunction and POFD.