Gromoll Jörg, Schulz Angela, Borta Heike, Gudermann Thomas, Teerds Katja J, Greschniok Annette, Nieschlag Eberhard, Seif Fritz J
Institute of Reproductive Medicine of the University, Munster, Germany.
Eur J Endocrinol. 2002 Nov;147(5):597-608. doi: 10.1530/eje.0.1470597.
Human chorionic gonadotropin/luteinizing hormone (hCG/LH) function in the male is mediated by the LH receptor (LHR) and is crucial for the normal development of internal and external genitalia. We report a 46, XY patient who presented at the age of 16 with a female phenotype and delayed puberty. Gonads were located bilaterally in the inguinal canal, removed surgically and showed hypoplastic Leydig cells. Immunostaining for the LHR revealed that some Leydig cell progenitors were positive, while others were negative, reflecting different developmental stages of Leydig cell maturation.
Molecular analysis of the LHR was performed on DNA extracted from blood samples of the patient, her parents and sister. The 11 exons of the LHR gene were amplified by PCR and subjected to further single stranded conformation polymorphism (SSCP) analysis. Aberrant migration patterns were observed in exon 7. Upon sequencing, a homozygous T to G transversion was identified, resulting in a F194V substitution located in the extracellular domain. The parents and sister were heterozygous carriers of this mutation. Functional studies in transiently transfected COS-7 cells with the F194V LHR mutation showed the lack of cAMP production upon hCG stimulation, indicating complete inactivation of the receptor due to impaired trafficking of the receptor to the membrane. The mutation is located within a stretch of five amino acids Ala (A)-Phe (F)-Asn (N)-Gly (G)-Thr (T), highly conserved in glycoprotein hormone receptors. For the follicle-stimulating hormone (FSH) receptor (FSHR) loss-of-function mutations have been allocated to this region, a homozygous A189V mutation resulting in a resistant ovary syndrome and impaired spermatogenesis and a heterozygous N191I mutation with no apparent phenotype. Further mutational and functional analysis of the AFN region in the LHR and FSHR revealed that the integrity of this amino acid sequence is crucial for receptor function.
人绒毛膜促性腺激素/促黄体生成素（hCG/LH）在男性中的功能由促黄体生成素受体（LHR）介导，对内外生殖器的正常发育至关重要。我们报告一名46,XY患者，16岁时表现出女性表型且青春期延迟。性腺双侧位于腹股沟管，手术切除后显示睾丸间质细胞发育不全。LHR免疫染色显示，一些睾丸间质细胞祖细胞呈阳性，而另一些呈阴性，反映了睾丸间质细胞成熟的不同发育阶段。
对患者及其父母和姐姐血液样本中提取的DNA进行LHR分子分析。通过聚合酶链反应（PCR）扩增LHR基因的11个外显子，并进行进一步的单链构象多态性（SSCP）分析。在外显子7中观察到异常迁移模式。测序后，鉴定出一个纯合的T到G颠换，导致位于细胞外结构域的F194V替换。父母和姐姐是该突变的杂合携带者。用F194V LHR突变体瞬时转染COS-7细胞的功能研究表明，hCG刺激后缺乏环磷酸腺苷（cAMP）产生，表明由于受体向膜的转运受损，受体完全失活。该突变位于一段由五个氨基酸组成的序列丙氨酸（A）-苯丙氨酸（F）-天冬酰胺（N）-甘氨酸（G）-苏氨酸（T）内，在糖蛋白激素受体中高度保守。对于促卵泡激素（FSH）受体（FSHR），功能丧失突变已定位到该区域，一个纯合的A189V突变导致抗性卵巢综合征和精子发生受损，以及一个无明显表型的杂合N191I突变。对LHR和FSHR中AFN区域的进一步突变和功能分析表明，该氨基酸序列的完整性对受体功能至关重要。
