The importance of the multiplex ligation-dependent probe amplification in the identification of a novel two-exon deletion of the NR5A1 gene in a patient with 46,XY differences of sex development

Orsolya Nagy,Judit Kárteszi,Rita Bertalan,Marianna Hartwig,Attila Patócs,Eszter Jávorszky,Tamás Tornóczky,István Balogh,Éva Erhardt,Anikó Ujfalusi

doi:10.1007/s11033-019-04980-8

Orsolya Nagy, Judit Kárteszi + Show 8 more

Open Access

https://doi.org/10.1007/s11033-019-04980-8

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Abstract

Gonadal dysgenesis (GD) is a rare cause of differences of sex development (DSD) with highly variable clinical and genetic conditions. Although identification of the causative genetic alterations can offer a clearer prognosis and personalized management to patients, more than 50% of the DSD cases still do not have an accurate genetic diagnosis. NR5A1 (previously known as SF-1), is a transcriptional regulator of genes required for normal development and functional maintenance of the gonads and the adrenal glands. Nucleotide sequence variants of the NR5A1 gene have been reported in numerous patients with GD with or without adrenal failure, however, microdeletion or partial deletion in the NR5A1 gene have been described only in a few GD cases. In this case study, we present a subject with female phenotype, mild clitoromegaly, partial GD and normal adrenal function. Cytogenetic analysis revealed a 46,XY SRY + karyotype. Microarray analysis did not identify pathogenic copy number variations, nor did panel sequencing of the most common DSD genes. Subsequently, multiplex ligation-dependent probe amplification (MLPA) was performed to test for small deletion/duplication of the most frequently affected genes associated with GD. Using this method, we have identified a novel heterozygous deletion involving exons 5 and 6 of the NR5A1 gene as the cause of abnormal sexual development of the patient. This report expands our knowledge about the range and pathogenetic role of NR5A1 mutations associated with partial gonadal dysgenesis in 46,XY DSD. Furthermore, our data emphasises the indispensable role of MLPA in the diagnosis of DSD with unclear etiology.

Highlights

Differences of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal and anatomical sex is atypical
Less than 50% of the DSDs with gonadal dysgenesis (GD) have specific molecular genetic diagnosis resulting from highly variable phenotype, heterogeneous genetic background and low genotype–phenotype correlation
Human NR5A1 mutations were first reported in association with 46,XY DSD and adrenal insufficiency [7], but later studies revealed that mutations are more frequent in 46,XY DSD patients without adrenal failure [8, 9]

Summary

Introduction

Differences of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal and anatomical sex is atypical. Molecular Biology Reports (2019) 46:5595–5601 be induced by numerical or structural sex chromosome aberrations, variations of genes involved in the gonadal and/or genitalal development or steroidogenesis, maternal factors, hormonal disturbances and epigenetic modifications [2–4]. Less than 50% of the DSDs with gonadal dysgenesis (GD) have specific molecular genetic diagnosis resulting from highly variable phenotype, heterogeneous genetic background and low genotype–phenotype correlation. The identified variants are mainly missense, nonsense, splicing mutations, small deletions and insertions [11–13]. Large scale mutations, such as microdeletion of 9q33 chromosomal region or partial gene deletions involving NR5A1 have been reported in only 5 cases with 46,XY DSD (Table 1) [14–18]

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