Kallmann syndrome in a patient with Weiss-Kruszka syndrome and a de novo deletion in 9q31.2

Phenotypic spectrum in Weiss-Kruszka syndrome caused by ZNF462 variants: Three new patients and literature review

Weiss-Kruszka Syndrome (WSKA) is caused by pathogenic variants in ZNF462 representing a rare autosomal dominant congenital anomaly syndrome. It is characterized by global developmental delay, hypotonia, feeding difficulties, and craniofacial abnormalities, documented in fewer than 30 patients. ZNF462, located on chromosome 9p31.2, is a transcription factor and has an important role during embryonic development and chromatin remodelling. Here, we report three new patients with WSKA, Through whole exome sequencing (WES) analysis, we identified two novel variants in three patients, two of whom are siblings. These variants (c.3078dup, p.Val1027Cysfs5 and c.4792A > T p.Lys1598*) in the ZNF462 gene are likely resulting in haploinsufficiency. Our patients help to further delineate the phenotype, genotype and potential therapeutic management strategies for WSKA. Since we report a second WSKA patient with an autoimmune disease further clinical and functional studies are needed to elucidate the association between this chromatin remodelling disorder and the development of autoimmune problems. In the future, collaborative efforts are encouraged to develop an episignature for WSKA, given the gene's function and associated patient phenotypes. This new technology has the potential to provide valuable insights into the disorder.

Analysis of glaucoma genes in Finnish patients with juvenile open-angle glaucoma

PURPOSE

To identify germline variants in myocilin (MYOC) and other known monogenic glaucoma genes in Finnish patients with juvenile open-angle glaucoma (JOAG).

METHODS

Finnish patients with JOAG treated between 2010 and 2018 at the Department of Ophthalmology, Helsinki University Hospital, Finland, were enrolled. We sequenced all exonic regions and flanking splice sites of MYOC for five patients and one healthy relative using Sanger sequencing. In 48 patients, we performed exome sequencing to identify variants also in 28 other glaucoma-related genes.

RESULTS

Fifty-three individuals with JOAG from 50 pedigrees, and one healthy relative, participated. The mean age at diagnosis was 30.8 years [SD 7.6; range 11 to 39]. Five probands had probably pathogenic variants in MYOC: c.1102C>T p.(Gln368Ter), c.1109C>T p.(Pro370Leu), c.1130C>T p.(Thr377Met), c.1132G>A p.(Asp378Asn) and c.1456C>T p.(Leu486Phe). Four of these patients had a family history of dominantly inherited JOAG. The frequency of MYOC variants was 10% (5 of 50 families). One patient and his mother with JOAG had a novel loss-of-function variant in the FOXC1 gene, c.366G>A p.(Trp122Ter). A patient with sporadic JOAG had a homozygous likely pathogenic variant in the LTBP2 gene, c.3938G>A p.(Cys1313Tyr). The genetic variants explained 14% (7 out of 50 families; 95% CI, 6%-23%) of JOAG in our cohort.

CONCLUSIONS

The frequency of pathogenic variants in previously known glaucoma-associated genes is low in Finnish patients with JOAG. Because of the distinct genetic background of Finns, it might be possible to identify novel glaucoma genes through our JOAG series in the future.

Further characterization of the 9q31 microdeletion phenotype; delineation of a common region of overlap containing ZNF462

BACKGROUND

Loss of function variants and whole gene deletions of ZNF462 has been associated with a novel phenotype of developmental delay/intellectual disability and distinctive facial features. Over two dozen cases have been reported to date and the condition is now known as Weiss-Kruszka syndrome (OMIM# 618619). There are several older reports in the literature and DECIPER detailing individuals with interstitial deletions of 9q31 involving the ZNF462 gene. Many of the characteristic facial features described in these microdeletion cases are similar to those who have been diagnosed with Weiss-Kruszka syndrome.

METHODS

We describe three additional patients with overlapping 9q31 deletions and compare the phenotypes of the microdeletion cases reported in the literature to Weiss-Kruszka syndrome.

RESULTS

Phenotypic overlap was observed between patients with 9q31 deletions and Weiss-Kruszka syndrome. Several additional features were noted in 9q31 deletion patients, including hearing loss, small head circumference, palate abnormalities and short stature.

CONCLUSIONS

The common region of overlap of microdeletion cases implicates ZNF462 as the main driver of the recognizable 9q31 microdeletion phenotype. The observation of additional features in patients with 9q31 microdeletions that are not reported in Weiss-Kruszka syndrome further suggests that other genes from the 9q31 region likely act synergistically with ZNF462 to affect phenotypic expression.

A genome-wide cross-cancer meta-analysis highlights the shared genetic links of five solid cancers

Breast, ovarian, prostate, lung, and head/neck cancers are five solid cancers with complex interrelationships. However, the shared genetic factors of the five cancers were often revealed either by the combination of individual genome-wide association study (GWAS) approach or by the fixed-effect model-based meta-analysis approach with practically impossible assumptions. Here, we presented a random-effect model-based cross-cancer meta-analysis framework for identifying the genetic variants jointly influencing the five solid cancers. A comprehensive genetic correlation analysis (genome-wide, partitioned, and local) approach was performed by using GWAS summary statistics of the five cancers, and we observed three cancer pairs with significant genetic correlation: breast-ovarian cancer (r _g = 0.221, p = 0.0003), breast-lung cancer (r _g = 0.234, p = 7.6 × 10^-6), and lung-head/neck cancer (r _g = 0.652, p = 0.010). Furthermore, a random-effect model-based cross-trait meta-analysis was conducted for each significant cancer pair, and we found 27 shared genetic loci between breast and ovarian cancers, 18 loci between breast and lung cancers, and three loci between lung and head/neck cancers. Functional analysis indicates that the shared genes are enriched in human T-cell leukemia virus 1 infection (HTLV-1) and antigen processing and presentation (APP) pathways. Our study investigates the shared genetic links across five solid cancers and will help to reveal their potential molecular mechanisms.

Time and dose-dependent effects of FGF8-FGFR1 signaling in GnRH neurons derived from human pluripotent stem cells

Fibroblast growth factor 8 (FGF8), acting through the fibroblast growth factor receptor 1 (FGFR1), has an important role in the development of gonadotropin-releasing hormone-expressing neurons (GnRH neurons). We hypothesized that FGF8 regulates differentiation of human GnRH neurons in a time- and dose-dependent manner via FGFR1. To investigate this further, human pluripotent stem cells were differentiated during 10 days of dual-SMAD inhibition into neural progenitor cells, followed either by treatment with FGF8 at different concentrations (25 ng/ml, 50 ng/ml or 100 ng/ml) for 10 days or by treatment with 100 ng/ml FGF8 for different durations (2, 4, 6 or 10 days); cells were then matured through DAPT-induced inhibition of Notch signaling for 5 days into GnRH neurons. FGF8 induced expression of GNRH1 in a dose-dependent fashion and the duration of FGF8 exposure correlated positively with gene expression of GNRH1 (P<0.05, Rs=0.49). However, cells treated with 100 ng/ml FGF8 for 2 days induced the expression of genes, such as FOXG1, ETV5 and SPRY2, and continued FGF8 treatment induced the dynamic expression of several other genes. Moreover, during exposure to FGF8, FGFR1 localized to the cell surface and its specific inhibition with the FGFR1 inhibitor PD166866 reduced expression of GNRH1 (P<0.05). In neurons, FGFR1 also localized to the nucleus. Our results suggest that dose- and time-dependent FGF8 signaling via FGFR1 is indispensable for human GnRH neuron ontogeny.

This article has an associated First Person interview with the first author of the paper.

Summary: This article demonstrates the essential role FGF8–FGFR1 signaling has in the development of gonadotropin-releasing hormone (GnRH)-expressing neurons by using a human stem cell model.

A Nonsense Variant of ZNF462 Gene Associated With Weiss-Kruszka Syndrome-Like Manifestations: A Case Study and Literature Review

Objective: This study aims to explore the clinical characteristics and genetic basis of a patient with unilateral ptosis and unilateral hearing impairment in pedigree analysis.

Methods: The clinical data of the child and his father were collected. The genomic DNA of the patient and his relatives were extracted from their peripheral blood samples and subjected to trio-whole-exome sequencing (trio-WES) and copy number variation analysis. Sanger sequencing was used to verify the potential variant.

Results: The sequencing analysis identified a heterozygous nonsense variant c.6431C > A (p.Ser2144*) in the ZNF462 gene (NM_021224.6) in the child and his father, whereas the locus in his asymptomatic mother, brother, and grandparents was found to be the wild type, which is an autosomal dominant inheritance. The new genetic variant has not been previously reported in the ClinVar and HGMD databases and the Genome Aggregation Database (gnomAD).

Conclusion: This is the first incidence of Weiss–Kruszka syndrome relating to the nonsense variant in the ZNF462 gene in China. The finding from this study is novel in its expansion of the variant spectrum of the ZNF462 gene and clarifies the genetic etiology of the patient and his father.

Acute lymphoblastic leukemia in a child with Weiss-Kruszka syndrome: Casual or causal association?

Weiss-Kruszka syndrome is a recently described genetic disorder characterized by craniofacial features, ptosis, dysgenesis of the corpus callosum, and neurodevelopmental impairment. It is caused by heterozygous loss-of-function variants
in ZNF462 gene. During the time, the original phenotype was expanded, including several complications, sensorineural hearing loss, congenital hypogonadotropic hypogonadism with anosmia and complete growth hormone deficiency associated with empty sella syndrome. Here we report the first case of Weiss-Kruszka syndrome, associated to a de novo 9q31.1q31.3 microdeletion showing an acute lymphoblastic leukemia. A speculation on the contribution of our case to the phenotypic expansion of WSKA is here discussed. More clinical and functional studies are needed to elucidate this association. A possible expansion of the WSKA phenotype is discussed.

Genetics of congenital olfactory dysfunction: a systematic review of the literature

Olfaction, as one of our 5 senses, plays an important role in our daily lives. It is connected to proper nutrition, social interaction, and protection mechanisms. Disorders affecting this sense consequently also affect the patients' general quality of life. Because the underlying genetics of congenital olfactory disorders (COD) have not been thoroughly investigated yet, this systematic review aimed at providing information on genes that have previously been reported to be mutated in patients suffering from COD. This was achieved by systematically reviewing existing literature on 3 databases, namely PubMed, Ovid Medline, and ISI Web of Science. Genes and the type of disorder, that is, isolated and/or syndromic COD were included in this study, as were the patients' associated abnormal features, which were categorized according to the affected organ(-system). Our research yielded 82 candidate genes/chromosome loci for isolated and/or syndromic COD. Our results revealed that the majority of these are implicated in syndromic COD, a few accounted for syndromic and isolated COD, and the least underly isolated COD. Most commonly, structures of the central nervous system displayed abnormalities. This study is meant to assist clinicians in determining the type of COD and detecting potentially abnormal features in patients with confirmed genetic variations. Future research will hopefully expand this list and thereby further improve our understanding of COD.