Craniofrontonasal syndrome (CFNS) is an X-linked disorder caused by EFNB1 mutations in which females are more severely affected than males. Severe male phenotypes are associated with mosaicism, supporting cellular interference for sex bias in this disease. Although many variants have been found in the coding region of EFNB1, only 2 pathogenic variants have been identified in the same nucleotide in 5′UTR, disrupting the stop codon of an upstream open reading frame (uORF). uORFs are known to be part of a wide range of post-transcriptional regulation processes, and just recently, their association with human diseases has come to light. In the present study, we analyzed EFNB1 in a female patient with typical features of CFNS. We identified a variant, located at c.-411, creating a new upstream ATG (uATG) in the 5′UTR of EFNB1, which is predicted to alter an existing uORF. Dual-luciferase reporter assays showed significant reduction in protein translation, but no difference in the mRNA levels. Our study demonstrates, for the first time, the regulatory impact of uATG formation on EFNB1 levels and suggests that this should be the target region in molecular diagnosis of CFNS cases without pathogenic variants in the coding and splice sites regions of EFNB1.

Craniofrontonasal syndrome (CFNS) is an X-linked disorder caused by EFNB1 mutations in which females are more severely affected than males. Severe male phenotypes are associated with mosaicism, supporting cellular interference for sex bias in this disease. Although many variants have been found in the coding region of EFNB1, only 2 pathogenic variants have been identified in the same nucleotide in 5′UTR, disrupting the stop codon of an upstream open reading frame (uORF). uORFs are known to be part of a wide range of post-transcriptional regulation processes, and just recently, their association with human diseases has come to light. In the present study, we analyzed EFNB1 in a female patient with typical features of CFNS. We identified a variant, located at c.-411, creating a new upstream ATG (uATG) in the 5′UTR of EFNB1, which is predicted to alter an existing uORF. Dual-luciferase reporter assays showed significant reduction in protein translation, but no difference in the mRNA levels. Our study demonstrates, for the first time, the regulatory impact of uATG formation on EFNB1 levels and suggests that this should be the target region in molecular diagnosis of CFNS cases without pathogenic variants in the coding and splice sites regions of EFNB1.

Background/Aims: Genetic imbalances are responsible for many cases of short stature of unknown etiology. This study aims to identify recurrent pathogenic copy number variants (CNVs) in patients with syndromic short stature of unknown cause. Methods: We selected 229 children with short stature and dysmorphic features, developmental delay, and/or intellectual disability, but without a recognized syndrome. All patients were evaluated by chromosomal microarray (array-based comparative genomic hybridization/single nucleotide polymorphism array). Additionally, we searched databases and previous studies to recover recurrent pathogenic CNVs associated with short stature. Results: We identified 32 pathogenic/probably pathogenic CNVs in 229 patients. By reviewing the literature, we selected 4 previous studies which evaluated CNVs in cohorts of patients with short stature. Taken together, there were 671 patients with short stature of unknown cause evaluated by chromosomal microarray. Pathogenic/probably pathogenic CNVs were identified in 87 patients (13%). Seven recurrent CNVs, 22q11.21, 15q26, 1p36.33, Xp22.33, 17p13.3, 1q21.1, 2q24.2, were observed. They are responsible for about 40% of all pathogenic/probably pathogenic genomic imbalances found in short stature patients of unknown cause. Conclusion: CNVs seem to play a significant role in patients with short stature. Chromosomal microarray should be used as a diagnostic tool for evaluation of growth disorders, especially for syndromic short stature of unknown cause.

Background/Aims: Genetic imbalances are responsible for many cases of short stature of unknown etiology. This study aims to identify recurrent pathogenic copy number variants (CNVs) in patients with syndromic short stature of unknown cause. Methods: We selected 229 children with short stature and dysmorphic features, developmental delay, and/or intellectual disability, but without a recognized syndrome. All patients were evaluated by chromosomal microarray (array-based comparative genomic hybridization/single nucleotide polymorphism array). Additionally, we searched databases and previous studies to recover recurrent pathogenic CNVs associated with short stature. Results: We identified 32 pathogenic/probably pathogenic CNVs in 229 patients. By reviewing the literature, we selected 4 previous studies which evaluated CNVs in cohorts of patients with short stature. Taken together, there were 671 patients with short stature of unknown cause evaluated by chromosomal microarray. Pathogenic/probably pathogenic CNVs were identified in 87 patients (13%). Seven recurrent CNVs, 22q11.21, 15q26, 1p36.33, Xp22.33, 17p13.3, 1q21.1, 2q24.2, were observed. They are responsible for about 40% of all pathogenic/probably pathogenic genomic imbalances found in short stature patients of unknown cause. Conclusion: CNVs seem to play a significant role in patients with short stature. Chromosomal microarray should be used as a diagnostic tool for evaluation of growth disorders, especially for syndromic short stature of unknown cause.