Case report of whole genome sequencing in the XY female: identification of a novel SRY mutation and revision of a misdiagnosis of androgen insensitivity syndrome

Novel Androgen Receptor Gene Variant Containing a Premature Termination Codon in a Patient with Androgen Insensitivity Syndrome

BACKGROUND

Androgen receptor (AR) mutations, which cause androgen insensitivity syndrome, impair the actions of 5α-dihydrotestosterone and testosterone, resulting in abnormal sexual development. In most cases, genetic aberrations of the AR are caused by substitutions, but also can result from mutations in splicing regions and deletions in the AR gene.

CASE

Our present report describes a female patient with 46,XY karyotype and normal female external genitalia. A novel de novo c.1669_1670insC insertion in the AR gene caused androgen insensitivity syndrome.

SUMMARY AND CONCLUSION

This report provides a detailed clinical characterization of the patient and a possible pathogenic mechanism leading to androgen insensitivity syndrome and should be particularly useful in genetic counseling.

Novel mutation in FTHL17 gene in pedigree with 46,XY pure gonadal dysgenesis

OBJECTIVE

To identify the genetic cause of a pedigree with four patients with 46,XY pure gonadal dysgenesis (PGD).

DESIGN

Genetic mutation study.

SETTING

Academic medical center.

PATIENT(S)

Four first cousins, from three households of a Chinese pedigree, affected by 46,XY PGD.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The patients were studied from clinical and genetic perspectives. Whole-genome sequencing was conducted in family members.

RESULT(S)

Four first cousins in the third generation were affected by 46,XY PGD. A specific familial characteristic was the prevalence of as high as 100% of gonadal tumors in patients. Whole-genome sequencing identified a new ferritin heavy chain-like 17 (FTHL17) mutation, c.GA442_443TT (p.E148L), which has the potential to interfere with protein function and cause 46,XY PGD. Moreover, the location (Xp21.2) of the FTHL17 gene proves that the family is X-linked recessive. In vitro functional study revealed that the perturbation of FTHL17 caused the decrease of protein expression and cell proliferation.

CONCLUSION(S)

We describe the first 46,XY PGD pedigree that may be attributed to mutations of the FTHL17 gene. We speculated that the FTHL17 gene is involved in the testis-determining pathway and tumorigenesis.

Genetic Testing in Endocrinology

The recent genomic revolution, characterised by surges in the number of available genetic tests and known genetic associations, calls for improved genetic literacy amongst medical scientists and clinicians. This has been driven by next generation sequencing, a technology allowing multiple genes to be sequenced in parallel, thereby reducing the time and financial costs associated with genetic testing in both research and clinical settings. Endocrinology is an intuitive setting in which to consider the principles of genetic testing because endocrine disorders are due to defects in circumscribed pathways, providing clues to candidate genes. This article discusses genetic testing in contemporary endocrine practice with reference to examples of endocrine genetic disorders or multisystem genetic disorders with endocrine manifestations. Monogenic disorders are prioritised as these form the bulk of endocrine genetic disorders and the associated genetic testing is readily understandable, clinically available and practice-changing. Although it remains true that genetic testing should be embarked upon only if the result will alter management, the clinical utility of genetic testing is often underestimated and there are expanding indications for genetic testing across all areas of endocrinology.