Functional analysis of novel desert hedgehog gene variants improves the clinical interpretation of genomic data and provides a more accurate diagnosis for patients with 46,XY differences of sex development

Katie Ayers, Jocelyn Van Den Bergen, Gorjana Robevska, Nurin Listyasari, Jamal Raza, Irum Atta, Stefan Riedl, Karen Rothacker, Catherine Choong, Sultana M.H. Faradz, Andrew Sinclair

Research output: Contribution to journalArticle

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Abstract

Background Desert hedgehog (DHH) gene variants are known to cause 46,XY differences/disorders of sex development (DSD). We have identified six patients with 46,XY DSD with seven novel DHH gene variants. Many of these variants were classified as variants of uncertain significance due to their heterozygosity or associated milder phenotype. To assess variant pathogenicity and to refine the spectrum of DSDs associated with this gene, we have carried out the first reported functional testing of DHH gene variant activity. Methods A cell co-culture method was used to assess DHH variant induction of Hedgehog signalling in cultured Leydig cells. Protein expression and subcellular localisation were also assessed for DHH variants using western blot and immunofluorescence. Results Our co-culture method provided a robust read-out of DHH gene variant activity, which correlated closely with patient phenotype severity. While biallelic DHH variants from patients with gonadal dysgenesis showed significant loss of activity, variants found as heterozygous in patients with milder phenotypes had no loss of activity when tested with a wild type allele. Taking these functional results into account improved clinical interpretation. Conclusion Our findings suggest heterozygous DHH gene variants are unlikely to cause DSD, reaffirming that DHH is an autosomal recessive cause of 46,XY gonadal dysgenesis. Functional characterisation of novel DHH variants improves variant interpretation, leading to greater confidence in patient reporting and clinical management.

Original languageEnglish
Pages (from-to)434-443
Number of pages10
JournalJournal of Medical Genetics
Volume56
Issue number7
DOIs
Publication statusPublished - 1 Jul 2019

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Sexual Development
XY Disorders of Sex Development 46
Genes
Coculture Techniques
Phenotype
46,XY Gonadal Dysgenesis
Gonadal Dysgenesis
Disorders of Sex Development
Leydig Cells
Fluorescent Antibody Technique
Virulence
Cultured Cells
Cell Culture Techniques
Western Blotting
Alleles
Proteins

Cite this

Ayers, Katie ; Van Den Bergen, Jocelyn ; Robevska, Gorjana ; Listyasari, Nurin ; Raza, Jamal ; Atta, Irum ; Riedl, Stefan ; Rothacker, Karen ; Choong, Catherine ; Faradz, Sultana M.H. ; Sinclair, Andrew. / Functional analysis of novel desert hedgehog gene variants improves the clinical interpretation of genomic data and provides a more accurate diagnosis for patients with 46,XY differences of sex development. In: Journal of Medical Genetics. 2019 ; Vol. 56, No. 7. pp. 434-443.
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abstract = "Background Desert hedgehog (DHH) gene variants are known to cause 46,XY differences/disorders of sex development (DSD). We have identified six patients with 46,XY DSD with seven novel DHH gene variants. Many of these variants were classified as variants of uncertain significance due to their heterozygosity or associated milder phenotype. To assess variant pathogenicity and to refine the spectrum of DSDs associated with this gene, we have carried out the first reported functional testing of DHH gene variant activity. Methods A cell co-culture method was used to assess DHH variant induction of Hedgehog signalling in cultured Leydig cells. Protein expression and subcellular localisation were also assessed for DHH variants using western blot and immunofluorescence. Results Our co-culture method provided a robust read-out of DHH gene variant activity, which correlated closely with patient phenotype severity. While biallelic DHH variants from patients with gonadal dysgenesis showed significant loss of activity, variants found as heterozygous in patients with milder phenotypes had no loss of activity when tested with a wild type allele. Taking these functional results into account improved clinical interpretation. Conclusion Our findings suggest heterozygous DHH gene variants are unlikely to cause DSD, reaffirming that DHH is an autosomal recessive cause of 46,XY gonadal dysgenesis. Functional characterisation of novel DHH variants improves variant interpretation, leading to greater confidence in patient reporting and clinical management.",
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Functional analysis of novel desert hedgehog gene variants improves the clinical interpretation of genomic data and provides a more accurate diagnosis for patients with 46,XY differences of sex development. / Ayers, Katie; Van Den Bergen, Jocelyn; Robevska, Gorjana; Listyasari, Nurin; Raza, Jamal; Atta, Irum; Riedl, Stefan; Rothacker, Karen; Choong, Catherine; Faradz, Sultana M.H.; Sinclair, Andrew.

In: Journal of Medical Genetics, Vol. 56, No. 7, 01.07.2019, p. 434-443.

Research output: Contribution to journalArticle

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T1 - Functional analysis of novel desert hedgehog gene variants improves the clinical interpretation of genomic data and provides a more accurate diagnosis for patients with 46,XY differences of sex development

AU - Ayers, Katie

AU - Van Den Bergen, Jocelyn

AU - Robevska, Gorjana

AU - Listyasari, Nurin

AU - Raza, Jamal

AU - Atta, Irum

AU - Riedl, Stefan

AU - Rothacker, Karen

AU - Choong, Catherine

AU - Faradz, Sultana M.H.

AU - Sinclair, Andrew

PY - 2019/7/1

Y1 - 2019/7/1

N2 - Background Desert hedgehog (DHH) gene variants are known to cause 46,XY differences/disorders of sex development (DSD). We have identified six patients with 46,XY DSD with seven novel DHH gene variants. Many of these variants were classified as variants of uncertain significance due to their heterozygosity or associated milder phenotype. To assess variant pathogenicity and to refine the spectrum of DSDs associated with this gene, we have carried out the first reported functional testing of DHH gene variant activity. Methods A cell co-culture method was used to assess DHH variant induction of Hedgehog signalling in cultured Leydig cells. Protein expression and subcellular localisation were also assessed for DHH variants using western blot and immunofluorescence. Results Our co-culture method provided a robust read-out of DHH gene variant activity, which correlated closely with patient phenotype severity. While biallelic DHH variants from patients with gonadal dysgenesis showed significant loss of activity, variants found as heterozygous in patients with milder phenotypes had no loss of activity when tested with a wild type allele. Taking these functional results into account improved clinical interpretation. Conclusion Our findings suggest heterozygous DHH gene variants are unlikely to cause DSD, reaffirming that DHH is an autosomal recessive cause of 46,XY gonadal dysgenesis. Functional characterisation of novel DHH variants improves variant interpretation, leading to greater confidence in patient reporting and clinical management.

AB - Background Desert hedgehog (DHH) gene variants are known to cause 46,XY differences/disorders of sex development (DSD). We have identified six patients with 46,XY DSD with seven novel DHH gene variants. Many of these variants were classified as variants of uncertain significance due to their heterozygosity or associated milder phenotype. To assess variant pathogenicity and to refine the spectrum of DSDs associated with this gene, we have carried out the first reported functional testing of DHH gene variant activity. Methods A cell co-culture method was used to assess DHH variant induction of Hedgehog signalling in cultured Leydig cells. Protein expression and subcellular localisation were also assessed for DHH variants using western blot and immunofluorescence. Results Our co-culture method provided a robust read-out of DHH gene variant activity, which correlated closely with patient phenotype severity. While biallelic DHH variants from patients with gonadal dysgenesis showed significant loss of activity, variants found as heterozygous in patients with milder phenotypes had no loss of activity when tested with a wild type allele. Taking these functional results into account improved clinical interpretation. Conclusion Our findings suggest heterozygous DHH gene variants are unlikely to cause DSD, reaffirming that DHH is an autosomal recessive cause of 46,XY gonadal dysgenesis. Functional characterisation of novel DHH variants improves variant interpretation, leading to greater confidence in patient reporting and clinical management.

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