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Open access

Fernanda A Correa, Ericka B Trarbach, Cintia Tusset, Ana Claudia Latronico, Luciana R Montenegro, Luciani R Carvalho, Marcela M Franca, Aline P Otto, Everlayny F Costalonga, Vinicius N Brito, Ana Paula Abreu, Mirian Y Nishi, Alexander A L Jorge, Ivo J P Arnhold, Yisrael Sidis, Nelly Pitteloud, and Berenice B Mendonca

The genetic aetiology of congenital hypopituitarism (CH) is not entirely elucidated. FGFR1 and PROKR2 loss-of-function mutations are classically involved in hypogonadotrophic hypogonadism (HH), however, due to the clinical and genetic overlap of HH and CH; these genes may also be involved in the pathogenesis of CH. Using a candidate gene approach, we screened 156 Brazilian patients with combined pituitary hormone deficiencies (CPHD) for loss-of-function mutations in FGFR1 and PROKR2. We identified three FGFR1 variants (p.Arg448Trp, p.Ser107Leu and p.Pro772Ser) in four unrelated patients (two males) and two PROKR2 variants (p.Arg85Cys and p.Arg248Glu) in two unrelated female patients. Five of the six patients harbouring the variants had a first-degree relative that was an unaffected carrier of it. Results of functional studies indicated that the new FGFR1 variant p.Arg448Trp is a loss-of-function variant, while p.Ser107Leu and p.Pro772Ser present signalling activity similar to the wild-type form. Regarding PROKR2 variants, results from previous functional studies indicated that p.Arg85Cys moderately compromises receptor signalling through both MAPK and Ca2 + pathways while p.Arg248Glu decreases calcium mobilization but has normal MAPK activity. The presence of loss-of-function variants of FGFR1 and PROKR2 in our patients with CPHD is indicative of an adjuvant and/or modifier effect of these rare variants on the phenotype. The presence of the same variants in unaffected relatives implies that they cannot solely cause the phenotype. Other associated genetic and/or environmental modifiers may play a role in the aetiology of this condition.

Open access

Marilena Nakaguma, Fernanda A Correa, Lucas S Santana, Anna F F Benedetti, Ricardo V Perez, Martha K P Huayllas, Mirta B Miras, Mariana F A Funari, Antonio M Lerario, Berenice B Mendonca, Luciani R S Carvalho, Alexander A L Jorge, and Ivo J P Arnhold

Aim

Congenital hypopituitarism has an incidence of 1:3500–10,000 births and is defined by the impaired production of pituitary hormones. Early diagnosis has an impact on management and genetic counselling. The clinical and genetic heterogeneity of hypopituitarism poses difficulties to select the order of genes to analyse. The objective of our study is to screen hypopituitarism genes (candidate and previously related genes) simultaneously using a target gene panel in patients with congenital hypopituitarism.

Methods

Screening of 117 subjects with congenital hypopituitarism for pathogenic variants in 26 genes associated with congenital hypopituitarism by massively parallel sequencing using a customized target gene panel.

Results

We found three novel pathogenic variants in OTX2 c.295C>T:p.Gln99*, GLI2 c.1681G>T:p.Glu561* and GHRHR c.820_821insC:p.Asp274Alafs*113, and the previously reported variants in GHRHR c.57+1G>A and PROP1 [c.301_302delAG];[c.109+1G>A].

Conclusions

Our results indicate that a custom-designed panel is an efficient method to screen simultaneously variants of biological and clinical relevance for congenital GH deficiency. A genetic diagnosis was possible in 5 out of 117 (4%) patients of our cohort. We identified three novel pathogenic variants in GHRHR, OTX2 and GLI2 expanding the spectrum of variants associated with congenital hypopituitarism.

Open access

Nathalia Liberatoscioli Menezes Andrade, Mariana Ferreira de Assis Funari, Alexsandra Christianne Malaquias, Paulo Ferrez Collett-Solberg, Nathalia L R A Gomes, Renata Scalco, Naiara Castelo Branco Dantas, Raissa C Rezende, Angelica M F P Tiburcio, Micheline A R Souza, Bruna L Freire, Ana C V Krepischi, Carlos Alberto Longui, Antonio Marcondes Lerario, Ivo J P Arnhold, Alexander A L Jorge, and Gabriela Andrade Vasques

Objective

Most children with short stature remain without an etiologic diagnosis after extensive clinical and laboratory evaluation and are classified as idiopathic short stature (ISS). This study aimed to determine the diagnostic yield of a multigene analysis in children classified as ISS.

Design and methods

We selected 102 children with ISS and performed the genetic analysis as part of the initial investigation. We developed customized targeted panel sequencing, including all genes already implicated in the isolated short-stature phenotype. Rare and deleterious single nucleotide or copy number variants were assessed by bioinformatic tools.

Results

We identified 20 heterozygous pathogenic (P) or likely pathogenic (LP) genetic variants in 17 of 102 patients (diagnostic yield = 16.7%). Three patients had more than one P/LP genetic alteration. Most of the findings were in genes associated with the growth plate differentiation: IHH (n  = 4), SHOX (n  = 3), FGFR3 (n  = 2), NPR2 (n  = 2), ACAN (n  = 2), and COL2A1 (n  = 1) or involved in the RAS/MAPK pathway: NF1 (n  = 2), PTPN11 (n  = 1), CBL (n  = 1), and BRAF (n  = 1). None of these patients had clinical findings to guide a candidate gene approach. The diagnostic yield was higher among children with severe short stature (35% vs 12.2% for height SDS ≤ or > −3; P = 0.034). The genetic diagnosis had an impact on clinical management for four children.

Conclusion

A multigene sequencing approach can determine the genetic etiology of short stature in up to one in six children with ISS, removing the term idiopathic from their clinical classification.