A novel mutation of AMH in three siblings with persistent Mullerian duct syndrome

Identification of AMH and AMHR2 Variants Led to the Diagnosis of Persistent Müllerian Duct Syndrome in Three Cases

Persistent Müllerian duct syndrome (PMDS) is a rare autosomal recessive disorder of sexual development in males, defined by the presence of Müllerian remnants with otherwise normal sexual differentiation. Mutations in anti-Müllerian hormone (AMH) and AMH receptor type 2 (AMHR2) genes are the main causes of PMDS. In this study, we performed molecular genetic analysis of 11 unrelated cryptorchidism patients using whole-exome sequencing and classified the variants. Three of the 11 patients had biallelic mutations in AMH or AMHR2. Case 1 carried a homozygous 4-bp deletion; c.321_324del:p.Q109Lfs*29 in exon 1 of AMH (NM_000479 transcript), which is a frameshift mutation, leading to the loss of function of AMH. Case 2 carried compound heterozygous mutations; c.494_502del (p.I165_A168delinsT) in exon 4 and g.6147C>A of AMHR2 (NM_001164690 transcript). Case 3 carried compound heterozygous mutations; c.G1168A (p.E390K) in exon 9 and c.A1315G (p.M439V) in exon 10 of AMHR2 (NM_001164690 transcript). All three patients were admitted due to azoospermia- and oligospermia-caused infertility. They were furtherly diagnosed with PMDS, as pelvic magnetic resonance imaging revealed the presence of Müllerian remnants. Our study suggests that PMDS and genetic analysis should be considered during the differential diagnosis of cryptorchidism.

Identification of four novel variant in the AMHR2 gene in six unrelated Turkish families

PURPOSE

Persistent Müllerian duct syndrome (PMDS) is characterized by the persistence of Müllerian structures in male with normal phenotype. Most cases occur as a result of mutations in the anti-Müllerian hormone (AMH) or AMHR2 genes. In this study, we aim to discuss the results of clinical, laboratory, and molecular genetic analysis of cases detected to have AMHR2 gene mutation.

METHODS

A total of 11 cases from 6 families were included in the study. AMHR2 gene mutation analyses were performed by sequencing of the coding exons and the exon-intron boundaries of the genes. The American College of Medical Genetics guidelines were used for the classification of the detected variants.

RESULTS

Six of the 11 cases were admitted due to bilateral undescended testes and five cases due to inguinal hernia (three transverse testicular ectopia and two hernia uterus inguinalis). All cases had normal AMH levels. Seven different variants were identified in the six families. The variants detected in four cases were considered novel (c.78del, c.71G > A, c.1460dup, c.1319A > G). Two of the novel variants were missense (exon 2 and exon 10) mutations, one was deletion (exon 2), and one duplication (exon 11).

CONCLUSION

We identified four novel mutations in the AMHR2 gene resulting in PMDS. Duplication mutation (c.1460dup) in the AMHR2 gene causing PMDS was demonstrated for the first time. The most important complications of PMDS are infertility and malignancy. Early diagnosis is vital to preventing malignancy. Vas deferens and vascular structures may be injured during orchiopexy. Therefore, patients should always be referred to experienced clinics.

Identification of two AMH gene variants in two unrelated patients with persistent Müllerian duct syndrome: one novel variant

INTRODUCTION

Persistent müllerian duct syndrome (PMDS) is a rare form of 46, XY disorder of sex development characterized by the persistence of the müllerian structures (uterus, fallopian tubes, the upper part of the vagina) in phenotypically and genotypically normal males. This disease occurs as a result of impairment in the synthesis, release or effect of anti-Müllerian hormone (AMH) during the embryonic period. Approximately 85-88% of PMDS cases have been reported to have AMH or AMHRII mutation.

CASE

Herein, we report two PMDS cases from unrelated two families who presented with bilateral undescended testes, persistence of müllerian remnants, and low/undetectable serum AMH levels. Molecular genetic analysis revealed two homozygous variants in AMH. The first one is a novel missense variant (c.1315C > T), the latter is a frameshift variant caused by a deletion (c.343_344delCT), which is less frequently reported type in AMH.

CONCLUSION

The diagnosis of PMDS should be kept in mind in patients with externally normal males, bilateral cryptorchidism, and signs of müllerian remnants on laparoscopy.

The possible role of AMH in shortening the gubernacular cord in testicular descent: A reappraisal of the evidence

BACKGROUND/AIM

Anti-Müllerian hormone (AMH), also called Müllerian inhibiting substance (MIS), is glycoprotein hormone secreted by the fetal Sertoli cells to regulate regression of the Müllerian ducts, the anlagen of the uterus, fallopian tubes, and upper vagina. After its existence was predicted in 1946 and its isolation and purification in the 1970's, a huge amount of information has been gathered on its molecular biology and function in the last 30-40years. Once thought to be a locally acting factor in the male fetus during sexual differentiation, it is now recognized as an endocrine hormone present in both sexes and with functions throughout life. One of the remaining controversies is the possible role of AMH during fetal testicular descent. In the human with aberrant AMH function, the boy has cryptorchidism with persistent Müllerian duct syndrome (PMDS), where the testes are often intraabdominal and on an abnormally long gubernacular cord. By contrast, in rodent models knockout of the AMH gene does not cause cryptorchidism.

METHODS/RESULTS

In this review we examined the evidence in the literature for and against a role for AMH in testicular descent and considered the implications of the different anatomy of the gubernacular cord in rodents versus children.

CONCLUSION

We conclude that AMH may have a role in shortening the gubernacular cord in humans which is concealed in rodent models by differences in anatomy of the gubernacular cord in rodents. The controversy could be resolved by re-examination of the gubernacular cord in boys with PMDS and mice with AMHKO.

TYPE OF STUDY

Review.

LEVEL OF EVIDENCE

V.