Case report: A case of Culler-Jones syndrome caused by a novel mutation of GLI2 gene and literature review

Culler-Jones syndrome is a rare clinical phenomenon with diverse manifestations and is prone to misdiagnosis. We report one patient who presented with a 10-year history of anosmia and a 1-year history of epididymal pain. Kallmann syndrome was suspected initially. The results of his laboratory tests, imaging, and genetic testing, however, combined to provide a conclusive diagnosis of Culler-Jones syndrome. With the aid of high-throughput sequencing technology, the GLI2 gene c.527A>G (p.Tyr176Cys) heterozygous mutation in the child was identified. No published works have yet described this mutation site. We described Culler-Jones syndrome in a child at length. We recommend that Culler-Jones syndrome be taken into account when considering the spectrum of disorders associated with abnormal growth and development in children. Once diagnosed, individualized hormone replacement treatment is required for each patient.

Novel GLI2 mutations identified in patients with Combined Pituitary Hormone Deficiency (CPHD): Evidence for a pathogenic effect by functional characterization

CONTEXT

The Gli-family of zinc-finger transcription factors regulates the Sonic Hedgehog (Shh) signalling pathway that plays a key role in early pituitary and ventral forebrain development. Heterozygous GLI2 loss of function mutations in humans have been reported in holoprosencephaly (HPE), HPE-like phenotypes associated with pituitary anomalies and combined pituitary hormone deficiency with or without other extra-pituitary findings.

OBJECTIVE

The aim of this study was the search for GLI2 mutations in a cohort of Italian CPHD patients and the assessment of a pathogenic role for the identified variants through in vitro studies.

PATIENTS

One hundred forty-five unrelated CPHD patients diagnosed with or without extra-pituitary manifestations were recruited from different Italian centres.

METHODS

The GLI2 mutation screening was carried out through direct sequencing of all the 13 exons and intron-exon boundaries. Luciferase reporter assays were performed to evaluate the role of the detected missense variants.

RESULTS

Five different novel heterozygous non-synonymous GLI2 variants were identified in five patients. The mutations were three missense (p.Pro386Leu, p.Tyr575His, p.Ala593Val), one frameshift (p.Val1111Glyfs*19) and one nonsense (p.Arg1226X). The latter two mutants are likely pathogenic since they lead to a truncated protein. The in vitro functional study of the plasmids bearing two of the three missense variants (namely p.Tyr575His and p.Ala593Val) revealed a significant reduction in transcriptional activity.

CONCLUSION

In conclusion, the analysis of GLI2 in individuals with CPHD led to the identification of five variations with a likely negative impact on the GLI2 protein, confirming that GLI2 is an important causative gene in CPHD. The functional in vitro study analysis performed on the missense variations were useful to strengthen the hypothesis of pathogenicity.

Two novel heterozygous missense variations within the GLI2 gene in two unrelated Argentine patients

Several heterozygous GLI2 gene mutations have been reported in patients with isolated GH deficiency (IGHD) or multiple pituitary hormone deficiency (MPHD) with or without other malformations. The primary aim of this study was to analyze the presence of GLI2 gene alterations in a cohort of patients with IGHD or MPHD and ectopic/absent posterior pituitary. The coding sequence and flanking intronic regions of GLI2 gene were amplified and directly sequenced from gDNA of 18 affected subjects and relatives. In silico tools were applied to identify the functional impact of newly found variants (Polyphen2, SIFT, Mutation Taster). We identified two novel heterozygous missense variations in two unrelated patients, p.Arg231Gln and p.Arg226Leu, located in the repressor domain of the protein. Both variations affect highly conserved amino acids of the Gli2 protein and were not found in the available databases. In silico tools suggest that these variations might be disease causing. Our study suggests that the GLI2 gene may be one of the candidate genes to analyze when an association of pituitary hormone deficiency and developmental defects in posterior pituitary gland. The highly variable phenotype found suggests the presence of additional unknown factors that could contribute to the phenotype observed in these patients.