Homozygous mutation within the conserved Ala-Phe-Asn-Glu-Thr motif of exon 7 of the LH receptor causes male pseudohermaphroditism
Homozygous mutation within the conserved Ala-Phe-Asn-Glu-Thr motif of exon 7 of the LH receptor causes male pseudohermaphroditism
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DOI：
10.1530/eje.0.1470597
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发表时间：
2002-11-01
影响因子：
5.8
通讯作者：
Seif, FJ
中科院分区：
文献类型：
--
作者：
Gromoll, J;Schulz, A;Seif, FJ
背景：男性的人绒毛膜促性腺激素/黄体生成素 (hCG/LH) 功能由 LH 受体 (LHR) 介导，对于内外生殖器的正常发育至关重要。我们报告了一名 46 岁、XY 患者，16 岁时就出现女性表型和青春期延迟。性腺位于腹股沟管的两侧，通过手术切除并显示发育不全的间质细胞。 LHR 免疫染色显示，一些 Leydig 细胞祖细胞呈阳性，而另一些则呈阴性，反映了 Leydig 细胞成熟的不同发育阶段。 方法和结果：对从患者及其父母和妹妹的血液样本中提取的 DNA 进行 LHR 的分子分析。通过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 中观察到异常的迁移模式。测序后，鉴定出纯合的 T 到 G 颠换，导致位于胞外结构域的 F194V 取代。父母和妹妹是这种突变的杂合携带者。对具有 F194V LHR 突变的瞬时转染 COS-7 细胞的功能研究表明，hCG 刺激后缺乏 cAMP 产生，表明由于受体向膜的运输受损而导致受体完全失活。该突变位于一段 5 个氨基酸 Ala (A)-Phe (F)-Asn (N)-Gly (G)-Thr (T) 内，在糖蛋白激素受体中高度保守。对于卵泡刺激素 (FSH) 受体 (FSHR) 功能丧失突变，已将其分配给该区域，纯合 A189V 突变会导致抵抗性卵巢综合征和精子发生受损，而杂合 NI 9 11 突变则无明显表型。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于受体功能至关重要。
Background: 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.Methods and Results: 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 NI 9 11 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.