Glycogen storage disease type I other diagnostic studies: Difference between revisions

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Latest revision as of 15:56, 22 December 2017

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Anmol Pitliya, M.B.B.S. M.D.[2]

Overview

Other studies used for diagnosis of glycogen storage disease type 1 include identification of proband by either molecular genetic testing or enzyme activity assay. Molecular genetic testing shows biallelic pathogenic variants in G6PC for patients with GSD type 1a and biallelic pathogenic variants in SLC37A4 for patients with GSD type 1b. Enzyme activity assay performed are glucose-6-phosphatase (G6Pase) catalytic activity and glucose-6-phosphate exchanger SLC37A4 (transporter) activity.

Other Diagnostic Studies

Glycogen storage disease type 1 is diagnosed by identification of proband by either of the following:^[1]

Molecular genetic testing

Molecular genetic testing shows:^[2]
- Biallelic pathogenic variants in G6PC for patients with GSD type 1a
- Biallelic pathogenic variants in SLC37A4 for patients with GSD type 1b

Molecular genetic testing
Genetic testing		Analysis performed
Serial single-gene testing		First sequence analysis of G6PC is done Sequence analysis of SLC37A4 if no G6PC pathogenic variants identified
Targeted analysis		For G6PC pathogenic variant Ashkenazi Jewish ancestry^[3] p.Arg83Cys analysis For G6PD pathogenic variant Old Order Amish ancestry p.Gln347Ter analysis
Multigene panel		Multiple genes are sequenced at the same time including G6PC, SLC37A4 and other related genes when differential diagnosis is considered
Comprehensive genomic testing	Exome sequencing	Considered if the diagnosis is not confirmed by serial single-gene testing and/or use of a multigene panel in an individual with features of GSD type I
Comprehensive genomic testing	Genome sequencing

Molecular genetic testing is preferred over enzyme activity assay due to:
- Relatively high sensitivity
- Need for liver biopsy for enzyme activity assay

Enzyme Activity Assay

Enzyme activity assay is performed on frozen liver (ample of 15-20 mg) obtained by percutaneous or open liver biopsy. Transport should be done on dry ice via overnight delivery to the clinical diagnostic laboratory.^[4]
Enzyme activity assay performed are:
- Glucose-6-phosphatase (G6Pase) catalytic activity
- Glucose-6-phosphate exchanger SLC37A4 (transporter) activity

References

↑ Bali DS, Chen YT, Austin S, et al. Glycogen Storage Disease Type I. 2006 Apr 19 [Updated 2016 Aug 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1312/
↑ Bali DS, Chen YT, Austin S, et al. Glycogen Storage Disease Type I. 2006 Apr 19 [Updated 2016 Aug 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1312/
↑ Ekstein J, Rubin BY, Anderson SL, Weinstein DA, Bach G, Abeliovich D; et al. (2004). "Mutation frequencies for glycogen storage disease Ia in the Ashkenazi Jewish population". Am J Med Genet A. 129A (2): 162–4. doi:10.1002/ajmg.a.30232. PMID 15316959.
↑ Bali DS, Chen YT, Austin S, et al. Glycogen Storage Disease Type I. 2006 Apr 19 [Updated 2016 Aug 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1312/

Template:WS Template:WH

[1] Bali DS, Chen YT, Austin S, et al. Glycogen Storage Disease Type I. 2006 Apr 19 [Updated 2016 Aug 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1312/

[2] Bali DS, Chen YT, Austin S, et al. Glycogen Storage Disease Type I. 2006 Apr 19 [Updated 2016 Aug 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1312/

[pmid15316959-3] Ekstein J, Rubin BY, Anderson SL, Weinstein DA, Bach G, Abeliovich D; et al. (2004). "Mutation frequencies for glycogen storage disease Ia in the Ashkenazi Jewish population". Am J Med Genet A. 129A (2): 162–4. doi:10.1002/ajmg.a.30232. PMID 15316959.

[4] Bali DS, Chen YT, Austin S, et al. Glycogen Storage Disease Type I. 2006 Apr 19 [Updated 2016 Aug 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1312/

[1]

[2]

[3]

[4]

@@ Line 1: / Line 1: @@
 __NOTOC__
 {{Glycogen storage disease type I}}
-{{CMG}}
+{{CMG}}; {{AE}} {{Anmol}}
 ==Overview==
+Other studies used for diagnosis of glycogen storage disease type 1 include identification of [[proband]] by either [[molecular]] [[genetic testing]] or [[Enzyme activity|enzyme activity assay]]. [[Molecular]] [[genetic testing]] shows biallelic [[pathogenic]] variants in [[G6PC]] for patients with GSD type 1a and biallelic [[pathogenic]] variants in [[SLC37A4]] for patients with GSD type 1b. [[Enzyme activity|Enzyme activity assay]] performed are [[glucose-6-phosphatase]] (G6Pase) [[catalytic activity]] and [[glucose-6-phosphate]] exchanger [[SLC37A4]] ([[transporter]]) activity.
 ==Other Diagnostic Studies==
-The diagnosis is definitively confirmed by liver [[biopsy]] with [[electron microscopy]] and [[assay]] of [[glucose-6-phosphatase]] activity in the tissue and/or specific gene testing, available in recent years.
+Glycogen storage disease type 1 is diagnosed by identification of [[proband]] by either of the following:<ref>Bali DS, Chen YT, Austin S, et al. Glycogen Storage Disease Type I. 2006 Apr 19 [Updated 2016 Aug 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1312/
+</ref>
+* [[Molecular]] [[genetic testing]]
+* [[Enzyme activity|Enzyme activity assay]]
+===Molecular genetic testing===
+*[[Molecular]] [[genetic testing]] shows:<ref>Bali DS, Chen YT, Austin S, et al. Glycogen Storage Disease Type I. 2006 Apr 19 [Updated 2016 Aug 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1312/
+</ref>
+**Biallelic [[pathogenic]] variants in [[G6PC]] for patients with GSD type 1a
+**Biallelic [[pathogenic]] variants in [[SLC37A4]] for patients with GSD type 1b
+{|
+! colspan="3" style="background:#4479BA; color: #FFFFFF;" align="center" + |Molecular genetic testing
+|-
+! colspan="2" style="background:#4479BA; color: #FFFFFF;" align="center" + |Genetic testing
+! style="background:#4479BA; color: #FFFFFF;" align="center" + |Analysis performed
+|-
+| colspan="2" style="background:#DCDCDC;" align="center" + |'''Serial single-gene testing'''
+| style="background:#F5F5F5;" + |
+*First sequence analysis of [[G6PC]] is done
+*Sequence analysis of [[SLC37A4]] if no [[G6PC]] [[pathogenic]] variants identified
+|-
+| colspan="2" style="background:#DCDCDC;" align="center" + |'''Targeted analysis'''
+| style="background:#F5F5F5;" + |
+*For [[G6PC]] [[pathogenic]] variant
+** Ashkenazi Jewish ancestry<ref name="pmid15316959">{{cite journal| author=Ekstein J, Rubin BY, Anderson SL, Weinstein DA, Bach G, Abeliovich D et al.| title=Mutation frequencies for glycogen storage disease Ia in the Ashkenazi Jewish population. | journal=Am J Med Genet A | year= 2004 | volume= 129A | issue= 2 | pages= 162-4 | pmid=15316959 | doi=10.1002/ajmg.a.30232 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15316959  }} </ref>
+*** p.Arg83Cys analysis
+*For [[G6PD]] [[pathogenic]] variant
+** Old Order Amish ancestry
+*** p.Gln347Ter analysis
+|-
+| colspan="2" style="background:#DCDCDC;" align="center" + |'''Multigene panel'''
+| style="background:#F5F5F5;" + |
+*Multiple genes are sequenced at the same time including  [[G6PC]], [[SLC37A4]] and other related genes when differential diagnosis is considered
+|-
+| rowspan="2" style="background:#DCDCDC;" align="center" + |'''Comprehensive genomic testing'''
+| style="background:#DCDCDC;" align="center" + |'''Exome sequencing'''
+| rowspan="2" style="background:#F5F5F5;" + |
+*Considered if the diagnosis is not confirmed by serial single-gene testing and/or use of a multigene panel in an individual with features of GSD type I
+|-
+| style="background:#DCDCDC;" align="center" + |'''Genome sequencing'''
+|}
+*[[Molecular]] [[genetic testing]] is preferred over [[Enzyme activity|enzyme activity assay]] due to:
+**Relatively high [[sensitivity]]
+**Need for [[liver biopsy]] for [[Enzyme activity|enzyme activity assay]]
+===Enzyme Activity Assay===
+*[[Enzyme activity|Enzyme activity assay]] is performed on frozen [[liver]] (ample of 15-20 mg) obtained by [[percutaneous]] or open [[liver biopsy]]. Transport should be done on dry ice via overnight delivery to the clinical diagnostic laboratory.<ref>Bali DS, Chen YT, Austin S, et al. Glycogen Storage Disease Type I. 2006 Apr 19 [Updated 2016 Aug 25]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1312/
+</ref>
+*[[Enzyme activity|Enzyme activity assay]] performed are:
+**[[Glucose-6-phosphatase]] (G6Pase) [[catalytic activity]]
+**[[Glucose-6-phosphate]] exchanger [[SLC37A4]] ([[transporter]]) activity
-[[Prenatal diagnosis]] has been made by fetal [[liver biopsy]] at 18-22 weeks of gestation, but no fetal treatment has been proposed. Prenatal diagnosis is possible with fetal [[DNA]] obtained by [[chorionic villus sampling]] when a fetus is known to be at risk.
 ==References==
 {{reflist|2}}
-{{WH}}
-{{WS}}
 [[Category:Endocrinology]]
-[[Category:Genetic disorders]]
 [[Category:Hepatology]]
-[[Category:Inborn errors of metabolism]]
 [[Category:Gastroenterology]]
+[[Category:Pediatrics]]
+[[Category:Up-To-Date]]
+[[Category:Genetic disorders]]
 [[Category:Metabolic disorders]]
-[[Category:Mature chapter]]
+{{WS}}
+{{WH}}