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Clinical, Biochemical, and Genetic Characterization of Glycogen Storage Type IX in a Child with Asymptomatic Hepatomegaly.

Kim JA, Kim JH, Lee BH, Kim GH, Shin YS, Yoo HW, Kim KM - Pediatr Gastroenterol Hepatol Nutr (2015)

Bottom Line: No other manifestations were evident except for hepatomegaly.His growth and development also have been proceeding normally.Diagnosed was made by histologic examination, an enzyme assay, and genetic testing with known c.3210_3212del (p.Arg1070del) mutation in PHKA2 gene.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea.

ABSTRACT
Glycogen storage disease type IX (GSD IX) is caused by a defect in phosphorylase b kinase (PhK) that results from mutations in the PHKA2, PHKB, and PHKG2 genes. Patients usually manifest recurrent ketotic hypoglycemia with growth delay, but some may present simple hepatomegaly. Although GSD IX is one of the most common causes of GSDs, its biochemical and genetic diagnosis has been problematic due to its rarity, phenotypic overlap with other types of GSDs, and genetic heterogeneities. In our report, a 22-month-old boy with GSD IX is described. No other manifestations were evident except for hepatomegaly. His growth and development also have been proceeding normally. Diagnosed was made by histologic examination, an enzyme assay, and genetic testing with known c.3210_3212del (p.Arg1070del) mutation in PHKA2 gene.

No MeSH data available.


Related in: MedlinePlus

Partial genomic sequences of the PHAK2 gene. (A) The patient is a homozygotefor the c.3210_3212del (p.Arg1070del) mutation. (B) His mother is a heterozygote for this mutation.
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Figure 2: Partial genomic sequences of the PHAK2 gene. (A) The patient is a homozygotefor the c.3210_3212del (p.Arg1070del) mutation. (B) His mother is a heterozygote for this mutation.

Mentions: With a high suspicion of GSD, genetic testing was performed to rule out GSD III (the AGL gene) and GSD VI (the PYGL gene). Genomic DNA was isolated from peripheral leukocytes of the patient with a PureGene blood kit (Qiagen, Hilden, Germany). All exons and their intronic boundaries of AGL and PYGL were amplified and sequenced using a BigDye Terminator V3.1 Cycle Sequencing Ready Reaction kit (Applied Biosystems, Foster City, CA, USA). He had normal sequences in the coding regions of the AGL and PYGL genes. We then checked PhK activity in the red blood cells, which was 15 µmol/min/g Hb (normal range, 100-300 µmol/min/g Hb). With a suspicion of GSD IXa, the PHKA2 gene was tested. Thirty-three exons and their intronic boundaries were investigated, revealing a previously reported mutation, c.3210_3212del (p.Arg1070del) (Fig. 2A) [7]. His mother carried the mutation as a heterozygote (Fig. 2B). However, there was no family history of liver disease on his maternal side.


Clinical, Biochemical, and Genetic Characterization of Glycogen Storage Type IX in a Child with Asymptomatic Hepatomegaly.

Kim JA, Kim JH, Lee BH, Kim GH, Shin YS, Yoo HW, Kim KM - Pediatr Gastroenterol Hepatol Nutr (2015)

Partial genomic sequences of the PHAK2 gene. (A) The patient is a homozygotefor the c.3210_3212del (p.Arg1070del) mutation. (B) His mother is a heterozygote for this mutation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493248&req=5

Figure 2: Partial genomic sequences of the PHAK2 gene. (A) The patient is a homozygotefor the c.3210_3212del (p.Arg1070del) mutation. (B) His mother is a heterozygote for this mutation.
Mentions: With a high suspicion of GSD, genetic testing was performed to rule out GSD III (the AGL gene) and GSD VI (the PYGL gene). Genomic DNA was isolated from peripheral leukocytes of the patient with a PureGene blood kit (Qiagen, Hilden, Germany). All exons and their intronic boundaries of AGL and PYGL were amplified and sequenced using a BigDye Terminator V3.1 Cycle Sequencing Ready Reaction kit (Applied Biosystems, Foster City, CA, USA). He had normal sequences in the coding regions of the AGL and PYGL genes. We then checked PhK activity in the red blood cells, which was 15 µmol/min/g Hb (normal range, 100-300 µmol/min/g Hb). With a suspicion of GSD IXa, the PHKA2 gene was tested. Thirty-three exons and their intronic boundaries were investigated, revealing a previously reported mutation, c.3210_3212del (p.Arg1070del) (Fig. 2A) [7]. His mother carried the mutation as a heterozygote (Fig. 2B). However, there was no family history of liver disease on his maternal side.

Bottom Line: No other manifestations were evident except for hepatomegaly.His growth and development also have been proceeding normally.Diagnosed was made by histologic examination, an enzyme assay, and genetic testing with known c.3210_3212del (p.Arg1070del) mutation in PHKA2 gene.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea.

ABSTRACT
Glycogen storage disease type IX (GSD IX) is caused by a defect in phosphorylase b kinase (PhK) that results from mutations in the PHKA2, PHKB, and PHKG2 genes. Patients usually manifest recurrent ketotic hypoglycemia with growth delay, but some may present simple hepatomegaly. Although GSD IX is one of the most common causes of GSDs, its biochemical and genetic diagnosis has been problematic due to its rarity, phenotypic overlap with other types of GSDs, and genetic heterogeneities. In our report, a 22-month-old boy with GSD IX is described. No other manifestations were evident except for hepatomegaly. His growth and development also have been proceeding normally. Diagnosed was made by histologic examination, an enzyme assay, and genetic testing with known c.3210_3212del (p.Arg1070del) mutation in PHKA2 gene.

No MeSH data available.


Related in: MedlinePlus