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Stepwise CaSR, AP2S1, and GNA11 sequencing in patients with suspected familial hypocalciuric hypercalcemia.
- Source :
-
Endocrine [Endocrine] 2017 Mar; Vol. 55 (3), pp. 741-747. Date of Electronic Publication: 2017 Feb 07. - Publication Year :
- 2017
-
Abstract
- Purpose: Patients with familial hyperparathyroidism and low urinary calcium excretion may have familial hypocalciuric hypercalcemia (FHH) with mutations in one of three genes: the calcium-sensing receptor (CaSR) defining FHH-type 1, the adaptor-related protein complex 2 (AP2S1) related to FHH-type 3 or the G-protein subunit alpha11 (GNA11) associated with FHH-type 2. We aimed to evaluate the presence of mutations in these genes and to identify phenotypic specificities and differences in these patients.<br />Subjects and Methods: Selected patients were recruited for genetic evaluation. After informed consent was signed, blood for DNA extraction was obtained and genetic sequencing of CaSR was done. In negative cases, we further performed sequencing of AP2S1 and GNA11.<br />Results: A total of 10 index cases were recruited. CaSR sequencing yielded three missense heterozygous mutations (30%): c.554G > A (p.I32V) previously characterized by our team, c.1394 G > A (p.R465Q) and a novel expected disease-causing mutation c.2479 A > C (p.S827R). We identified 2 additional patients (20%) carrying the deleterious recurrent mutation c.44G > T (p.R15L) in the AP2S1 gene. No GNA11 mutation was found. Clinically, patients with AP2S1 mutations had significant cognitive and behavioral disorders, and higher blood calcium and magnesium levels than patients with FHH1.<br />Conclusion: CaSR and AP2S1 sequencing is worthwhile in patients with familial hyperparathyroidism and phenotype suggesting FHH as it can diagnose up to 50% of cases. GNA11 mutations seem much rarer. Learning disabilities in these patients, associated with higher serum calcium and magnesium levels may suggest the presence of AP2S1 rather than CaSR mutation and may guide the first step in the genetic evaluation.
- Subjects :
- Adult
Child, Preschool
Female
Humans
Hypercalcemia diagnosis
Hypercalcemia genetics
Infant, Newborn
Male
Oligonucleotide Array Sequence Analysis
Pedigree
Young Adult
Adaptor Protein Complex 2 genetics
Adaptor Protein Complex sigma Subunits genetics
GTP-Binding Protein alpha Subunits genetics
Hypercalcemia congenital
Mutation
Receptors, Calcium-Sensing genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1559-0100
- Volume :
- 55
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Endocrine
- Publication Type :
- Academic Journal
- Accession number :
- 28176280
- Full Text :
- https://doi.org/10.1007/s12020-017-1241-5