Species: mouse
Mutation name: None
type: null mutation
fertility: subfertile
Comment: Rankin et al. (1999) have used targeted mutagenesis in embryonic stem cells to create mouse lines (Zp1(tm/tm)) lacking ZP1. Although a zona pellucida composed of ZP2 and ZP3 was formed around growing Zp1(tm/tm) oocytes, the matrix was more loosely organized than zonae around normal oocytes. In some Zp1 null follicles, this structural abnormality resulted in ectopic clusters of granulosa cells, lodged between the zona matrix and the oolemma, that perturbed normal folliculogenesis, Comparable numbers of eggs were ovulated from Zp1 null females and normal females following hormonal stimulation. However, fewer two-cell embryos were recovered and litters were significantly smaller than those produced by normal mice. Therefore, although mouse ZP1 is not essential for sperm binding or fertilization, it is required for the structural integrity of the zona pellucida to minimize precocious hatching and reduced fecundity.

Species: human
Mutation name: None
type: naturally occurring
fertility: infertile - ovarian defect
Comment: Mutant ZP1 in familial infertility. Huang HL 2014 et al. The human zona pellucida is composed of four glycoproteins (ZP1, ZP2, ZP3, and ZP4) and has an important role in reproduction. Here we describe a form of infertility with an autosomal recessive mode of inheritance, characterized by abnormal eggs that lack a zona pellucida. We identified a homozygous frameshift mutation in ZP1 in six family members. In vitro studies showed that defective ZP1 proteins and normal ZP3 proteins colocalized throughout the cells and were not expressed at the cell surface, suggesting that the aberrant ZP1 results in the sequestration of ZP3 in the cytoplasm, thereby preventing the formation of the zona pellucida around the oocyte. /////////////////////////

Species: human
Mutation name:
type: naturally occurring
fertility: infertile - ovarian defect
Comment: Novel zona pellucida gene variants identified in patients with oocyte anomalies. Yang P et al. (2017) To detect ZP (zona pellucida) gene (ZP1-ZP4) mutations in patients with oocyte anomalies. Case-control genetic study. University-based reproductive medicine center. A total of 92 infertile patients with repeated cycles of oocyte maturation arrest (group I, n = 49) or oocyte morphologic defect (group II, n = 43) as well as 373 healthy controls. Genomic DNA extracted from peripheral blood and coding regions of ZP genes amplified by polymerase chain reaction and sequenced by a DNA analyzer. Variant prediction of ZP genes with software. In group I with oocyte maturation arrest, no novel variants were found. In group II with oocyte morphologic defects, four novel variants, two in the ZP1 gene [c.247T>C (p.W83R) and c.1413G>A (p.W471X)] and two in the ZP2 gene [c.1599G>T (p.R533S) and c.1696T>C (p.C566R)] were detected in 4 of 43 patients (approximately 9%) but were absent from the controls. Protein alignments showed that the four variants were highly conserved among different species, and all four variants were predicted to be deleterious by gene software predictions. ZP gene variants may account for patients with oocyte morphologic abnormalities but not for those with oocyte maturation arrest.//////////////////

Species: human
Mutation name:
type: naturally occurring
fertility: infertile - ovarian defect
Comment: Compound heterozygous ZP1 mutations cause empty follicle syndrome in infertile sisters. Sun L et al. (2019) Empty follicle syndrome (EFS) is a condition in which no oocyte is retrieved from mature follicles after proper ovarian stimulation in an in vitro fertilization procedure. Genetic evidence accumulates for the etiology of recurrent EFS without pharmacological or iatrogenic problems. In this study, we present two infertile sisters in a family with EFS after three cycles of standard ovarian stimulation with human chorionic gonadotrophin and/or gonadotropin-releasing hormone agonist therapy. Via whole-exome sequencing and cosegregation test, we identified compound heterozygous mutations in the gene of ZP1 in both of the infertile sisters. Coimmunoprecipitation tests and homology modeling analysis confirmed that both mutated ZP1 disrupt the formation of oocyte zona pellucida by interrupting the interaction among ZP1, ZP2, and ZP3. We thus propose that the specific mutations in ZP1 gene render a causality for the intractable EFS.//////////////////

Species: human
Mutation name:
type: naturally occurring
fertility: infertile - ovarian defect
Comment: Homozygous Splice Site Mutation in ZP1 Causes Familial Oocyte Maturation Defect. Okutman Ö et al. (2020) In vitro fertilization (IVF) involves controlled ovarian hyperstimulation using hormones to produce large numbers of oocytes. The success of IVF is tightly linked to the availability of mature oocytes. In most cases, about 70% to 80% of the oocytes are mature at the time of retrieval, however, in rare instances, all of them may be immature, implying that they were not able to reach the metaphase II (MII) stage. The failure to obtain any mature oocytes, despite a well conducted ovarian stimulation in repeated cycles is a very rare cause of primary female infertility, for which the underlying suspected genetic factors are still largely unknown. In this study, we present the whole exome sequencing analysis of a consanguineous Turkish family comprising three sisters with a recurrent oocyte maturation defect. Analysis of the data reveals a homozygous splice site mutation (c.1775-3C>A) in the zona pellucida glycoprotein 1 (ZP1) gene. Minigene experiments show that the mutation causes the retention of the intron 11 sequence between exon 11 and exon 12, resulting in a frameshift and the likely production of a truncated protein.//////////////////

Species: human
Mutation name:
type: naturally occurring
fertility: infertile - ovarian defect
Comment: A novel homozygous nonsense ZP1 variant causes human female infertility associated with empty follicle syndrome (EFS). Xu Q et al. (2020) Empty follicle syndrome (EFS) is a rare but severe condition in which no oocyte is recovered in female patients undergoing in vitro fertilization (IVF) after sufficient ovarian response to hormonal trigger. Accumulating evidence highlights the genetic basis of EFS occurrence. In this study, we report a patient with primary infertility showing the characteristics of EFS from a consanguineous family. Under the treatment of assisted reproductive technique (ART), no oocyte was retrieved following the aspiration of mature follicles. Through whole-exome sequencing (WES), we discovered a novel recessively transmitted mutation in ZP1 (c.769 C>T, p. Q257*). In vitro Co-immunoprecipitation assays showed that mutant ZP1 protein failed to interact with either ZP2 or ZP3, which explains the degenerated oocytes in the patient with EFS. Together, our data further expand the spectrum of ZP1 mutations that are associated with human EFS and thus provide novel insight into the diagnosis of EFS patients.//////////////////

Species: human
Mutation name:
type: naturally occurring
fertility: infertile - ovarian defect
Comment: Novel biallelic loss-of-function variants in ZP1 identified in an infertile female with empty follicle syndrome. Liu M et al. (2020) Empty follicle syndrome (EFS) refers to the inability to obtain mature oocytes after appropriate ovarian stimulation during the process of in vitro fertilization (IVF). However, the specific cause and mechanism of action underlying EFS remain to be further explored. Herein we aimed to investigate the clinical and genetic characteristics of EFS. After data were collected in an infertile family, we performed whole-exome sequencing (WES) on the patient and confirmed the pathogenic mutations through Sanger sequencing. Western immunoblotting, immunofluorescence staining, and minigene assay were further used to investigate the negative effects of these mutations. Absence of oocytes was observed over 2 cycles of IVF in the patient, and we evaluated the novel compound heterozygous mutations c.2T>A (p. M1K) and c.1112+1G>T of the zona pellucida glycoprotein 1 gene (ZP1, MIM# 195000) by WES. For the family under study, EFS was classified as an autosomal recessive inheritance pattern. The results of western blotting and immunofluorescence staining analyses confirmed that the missense mutation of c.2T>A [p. M1K] resulted in almost missing protein production. Additionally, using a minigene assay, we demonstrated the deleterious effect on the ZP1 gene of the splice site mutation c.1112+1G>T, which caused truncation of ZP1 protein. The compound heterozygous mutations of ZP1 gene identified in this study by genetic and functional experiments constituted a novel genetic cause of EFS, and further study will expand its use in the clinical and molecular diagnoses of EFS.//////////////////

Species: human
Mutation name:
type: naturally occurring
fertility: infertile - ovarian defect
Comment: Novel mutations in ZP1 and ZP2 cause primary infertility due to empty follicle syndrome and abnormal zona pellucida. Luo G et al. (2020) Mutations in the zona pellucida glycoprotein genes have been reported to be associated with empty follicle syndrome (EFS) and abnormal zona pellucida (ZP). In this study, we performed genetic analysis in the patients with female infertility due to abnormal zona pellucida and empty follicle syndrome to identify the disease-causing gene mutations in these patients. We characterized three patients from two independent families who had suffered from empty follicle syndrome or abnormal zona pellucida. Whole exome sequencing and Sanger sequencing were used to identify the mutations in the families. Western blot was used to check the expression of wild type and mutant disease genes. We identified two novel mutations in these patients, including a novel compound heterozygous mutation (c.507delC, p. His170fs; c.239 G>A, p. Cys80Tyr and c.241 T>C, p. Tyr81His) in ZP1 gene and a compound mutation in ZP2 gene (c.860_861delTG, p.Val287fs and c.1924 C>T, p.Arg642Ter). Expression of the mutant ZP1 protein (p. Cys80Tyr and p. Tyr81His) is significantly decreased compared with the wild-type ZP1. Other three mutations produce truncated proteins. Our findings expand the mutational spectrum of ZP1 and ZP2 genes associated with EFS and abnormal oocytes and provide new support for the genetic diagnosis of female infertility.//////////////////

Species: human
Mutation name:
type: naturally occurring
fertility: infertile - ovarian defect
Comment: Novel mutations in ZP1: Expanding the mutational spectrum associated with empty follicle syndrome in infertile women. Wu L et al. (2021) Empty follicle syndrome (EFS) is a serious and complex reproductive complication for infertile women suffering from the recurrent failure of oocyte retrieval in an in vitro fertilization procedure, and its pathogenesis remains obscure. Increasing evidence highlights the genetic basis of EFS occurrence. In this study, we identified two novel missense mutations (c.1127G > A, p.C376Y and c.325C > T, p.R109C), two novel frameshift mutations (c.800_801delAG, p.E267Gfs*80 and c.1815_1825delGGTCCTTTTGC, p.V606Afs*42), one novel nonsense mutation (c.199G > T, p.E67Ter), and three reported mutations (c.769C > T, p.Q257Ter; c.1430 + 1G > T, p.C478Ter and c.1169_1176delTTTTCCCA, p.I390Tfs*16) in five unrelated probands, showing similar EFS manifestations, which expands the mutational spectrum of individuals with autosomal recessive ZP1. Current research will provide a better understanding of the biological functions of ZP1, and some insight into the determination of ZP1 variation as an additional rule for assessing the EFS disease.//////////////////

Species: rat
Mutation name:
type: null mutation
fertility: infertile - ovarian defect
Comment: Mutant Zp1 impedes incorporation of ZP3 and ZP4 in the zona pellucida, resulting in zona absence and female infertility in rats. Lv C et al. (2021) The zona pellucida (ZP) plays vital roles in reproductive processes including oogenesis, fertilization and preimplantation development. Both human and rat ZP consist of four glycoproteins, called ZP1, ZP2, ZP3 and ZP4. Our previous research reported a novel Zp1 mutation in cases of human infertility, associated with an abnormal phenotype involving the absence of the zona pellucida. Here, we developed a homologous rat strain to investigate the pathogenic effect. The ovaries of homozygous (Zp1MT/MT) females possessed both growing and fully grown oocytes; the oocytes completely lacked a zona pellucida, but ZP1 was detectable inside the cytoplasm. Only 1-2 eggs were recovered from oviducts of superovulated Zp1MT/MT females, while ≈ 21 eggs were recovered from superovulated Zp1WT/WT females. The eggs of Zp1MT/MT females were not surrounded by a zona pellucida and lost their fertilization capacity in vitro. Zp1MT/MT females mated with wild-type males failed to become pregnant. Studies in 293 T cells showed that mutant Zp1 resulted in a truncated ZP1 protein, which might be intracellularly sequestered and interact with wild-type ZP3 or ZP4. Our results suggest that the Zp1 point mutation led to infertility and loss of the ZP in oocytes in rats.//////////////////

Species: human
Mutation name:
type: naturally occurring
fertility: infertile - ovarian defect
Comment: A novel homozygous nonsense mutation in zona pellucida 1 (ZP1) causes human female empty follicle syndrome. Wang J et al. (2021) To identify a pathogenic gene mutation in a female infertility proband characterized by empty follicle syndrome (EFS) and explore the genetic cause of EFS. Whole exome sequencing (WES) was performed to identify the candidate pathogenic mutation. Sanger sequencing was used to validate the mutation in family members. The pathogenicity of the identified variant and its possible effects on the protein were evaluated with in silico tools. Immunofluorescence staining was used to study the possible mechanism of the mutation on affected oocyte. We identified a family with a novel homozygous nonsense mutation in zona pellucida 1 (ZP1) (c.199G > T [p.Glu67Ter]). Based on bioinformatics analysis, the mutation was predicted to be pathogenic. This variant generates a premature stop codon in exon 2 at the 199th nucleotide, and was inferred to result in a truncated ZP1 protein of 67 amino acids at the ZP-N1 domain. An in vitro study showed that the oocyte of the EFS proband was degenerated and the zona pellucida was absent. Additionally, the mutant ZP1 proteins were localized in the cytoplasm of the degenerated oocyte but not at the surface. The novel mutation in ZP1 is a genetic cause of female infertility characterized by EFS. Our finding expands the genetic spectrum for EFS and will help justify the EFS diagnosis in patients.//////////////////