Mutations In GNAS Gene Research Articles

Restoration of ovulation after unilateral ovariectomy in a woman with McCune–Albright syndrome: a case report

McCune-Albright syndrome (MAS) is characterized by peripheral precocious puberty, café-au-lait spots, and polyostotic fibrous dysplasia. This syndrome is due to a post-zygotic mutation of the GNAS1 gene with mosaic distribution and unilateral predominance. Clinical manifestations depend on the tissues carrying the mutation. We describe the ovarian function before and after unilateral ovariectomy in a woman with MAS and bilateral distribution of the GNAS1 gene mutation. A 33-year-old patient, previously diagnosed as having MAS, presented irregular menstrual cycles (30-180 days) and monophasic temperature curves. Transvaginal ultrasound and blood tests were repeated at 3-day intervals over 3 months. Findings included a persistent quiescent left ovary, a persistent polycystic right ovary, constantly high estradiol-17beta (E2) levels, and very low FSH and LH levels. She also presented severe persistent pelvic pain. Because of unilateral ovarian activity, a unilateral right ovariectomy was performed as well as biopsy of the remaining left ovary. A GNAS1 gene mutation was identified in both ovaries. A regular monthly menstrual cycle was immediately restored. On day 3 of the menstrual cycle, E2 level was 30 pg/ml, FSH level was 7.5 mIU/ml, and LH level was 6.4 mIU/ml. On day 17, pelvic ultrasound showed one follicle of 25 mm in the left ovary. On day 21, the progesterone level was 13.1 ng/ml. This is the first report of ovulation being restored following unilateral ovariectomy in an adult patient suffering from severe MAS with GNAS1 gene mutation identified in both ovaries.

GNAS1 gene abnormality in pseudohypoparathyroidism I a

Pseudophypoparathyroidism (PHP) is characterized by hypocalcemia, hyperphosphatemia and elevated levels of parathyroid hormone (PTH) due to resistance to PTH. PHP type I a is caused by heterozygous inactivating mutation of the GNAS1 gene, which encodes signal transducer, Gsalpha. PHP type I a is associated with Albright's osteodystrophy (AHO). Those patients who have AHO phenotype without hormone resistance are affected by pseudopseudohypoparathyroidism.

SUDDEN INFANT DEATH SYNDROME AND ACTIVATING GNAS1 GENE MUTATIONS

GNAS1 gene mutations cause the McCune-Albright syndrome. Some patients may develop unusual, severe, nonendocrine manifestations that may lead to death. We postulate that some cases of sudden infant death syndrome (SIDS) might be caused by GNAS1 gene mutations affecting vital organs. We studied two GNAS1 gene mutations (R201H and R201C) by allele specific PCR and enzymatic digestion in pulmonary, pancreas, liver, kidney, and heart tissue from 29 infants who suffered SIDS. The infants died at age 96 ± 78 days. At the time of death, children had a height Z score of −0,04 ± 0,95, a weight Z score of 0,04 ± 0,91, and a weight for length Z score of 0,1 ± 0,83. The molecular study by both techniques did not reveal any GNAS1 mutations in the tissues examined. We conclude that GNAS1 gene mutations do not appear to be present in tissues of infants with SIDS.

McCune-Albright Syndrome with Acromegaly and Fibrous Dysplasia Associated with the GNAS Gene Mutation Identified by Sensitive PNA-clamping Method

A 16-year-old girl presented with McCune-Albright syndrome associated with acromegaly and fibrous dysplasia. Brain MRI demonstrated a pituitary tumor. X-ray films showed bone deformities, and 99TmO4 bone scintigraphy revealed increased uptake of radioactivity in the affected bones. Although the serum FGF23 level was increased, the serum calcium, phosphate, and active vitamin D levels were all within normal limits. GNAS gene mutation was detected at neither codon 201 nor 227 by conventional PCR-based direct sequencing analysis. We performed a selective PCR with peptide nucleic acid (PNA) clamping to increase the sensitivity for gene mutation detection and identified the R201C GNAS mutation.

Activating GNAS1 gene mutations in patients with premature thelarche

Objective To identify GNAS1 gene mutations in girls with exaggerated and/or chronic fluctuating thelarche for at least 1-year duration with no other signs of precocious puberty, skeletal dysplasia, or typical skin lesions of McCune-Albright syndrome. Study design We studied the GNAS1 gene mutation by allele-specific polymerase chain reaction and enzymatic digestion in leukocyte DNA in 23 girls previously described. Results Fluctuating thelarche was present in 14 girls and exaggerated thelarche was observed in 9. Molecular study revealed that 6 girls had a substitution of arginine by histidine in codon 201 (R201H [+]). Three R201H (+) girls reached their menarche at a mean chronologic age of 10.8 years and 9 of the R201H (−) girls at a mean age of 11 years. Conclusions Activating mutations of GNAS1 gene may be observed in some girls with chronic fluctuating and/or exaggerated thelarche, without other classic signs of McCune-Albright syndrome.

Characterization of panoramic radiographic features of maxillo-mandibular fibrous dysplasia in Mccune-Albright Syndrome

Fibrous dysplasia (FD) is a rare skeletal disease often associated with McCune-Albright Syndrome (MAS); a triad of FD, café-au-lait skin hyperpigmentation and endocrinopathies. It is caused by activating postzygotic GNAS1 gene mutations. Multiple bones may be affected including maxilla and mandible. Also, endocrinopathies in MAS can further influence bone metabolism.

Analyses of variable panoramic radiographic characteristics of maxillo-mandibular fibrous dysplasia in McCune-Albright syndrome.

Fibrous dysplasia (FD) is a rare skeletal disease caused by activating GNAS1 gene mutations often found in association with the McCune-Albright syndrome (MAS). Multiple bones may be affected in FD, including maxilla and mandible. Patients with MAS have different endocrinopathies that can further influence bone metabolism. The purposes of this cross-sectional study are to characterize FD panoramic radiographic patterns, and to evaluate the effects of age, endocrinopathies and renal phosphate wasting on radiographic characteristics of maxillo-mandibular FD in MAS. Fifty-one consecutive MAS patients were screened and panoramic radiographs of 43 patients with craniofacial FD were evaluated and analyzed for FD involvement. Clinical chemistries were evaluated for associations between radiographic patterns and age, endocrinopathies or renal phosphate wasting using Fisher's Exact Test. Four types of radiographic changes were observed: ground glass (granular/condensed trabeculae), radiolucent (lytic), mixed radiolucent/radio-opaque (mixed density) or radio-opaque (sclerotic). Masking or displacement of the maxillary sinus (range: 77.8-86.4%) and mandibular canal (range: 55.6-75.0%) were prevalent in FD sites. Sixty-three percent of the MAS patients had multiple dysregulated endocrine/metabolic functions, the most common were hyperthyroidism, precocious puberty and renal phosphate wasting. There were no statistically significant associations between radiographic patterns and age, endocrinopathies or renal phosphate wasting. Maxillo-mandibular FD images in panoramic radiographs fall within a spectrum of four different patterns. Patients with facial asymmetry and any of these radiographic patterns should be promptly referred for further radiographic tests and endocrine evaluation if MAS is suspected.

Dental characteristics of fibrous dysplasia and McCune-Albright syndrome.

Fibrous dysplasia (FD) is a skeletal disorder often associated with McCune-Albright syndrome, a rare multisystem disorder caused by GNAS1 gene mutation. FD frequently affects the craniofacial bones, including the maxilla and the mandible; nevertheless, its effects on dental tissues and the implications for dental care remain unclear. The aim of this study was to characterize the dental features associated with FD and the reaction of affected bones to routine dental therapy. Study design Thirty-two patients with FD underwent dental evaluation and endocrine testing as part of the diagnosis of FD/McCune-Albright syndrome. Any dental anomalies were recorded, and the associations between endocrinopathies and dental anomalies were analyzed statistically by means of the paired t test. Eighty-four percent had FD in the maxilla and/or mandible; endocrine dysfunction; and/or renal phosphate wasting. The caries index scores were 2.9 (ages 4-17 years) and 9.6 (ages 18-50 years). Malocclusion (81%) and other prevalent dental anomalies (41%) included tooth rotation, oligodontia, and taurodontism. The expansion of the maxilla or mandible by FD did not distort the dental arch curvature, and routine dental therapies such as extractions, restorations, and orthodontic treatment did not exacerbate FD lesions. Maxillomandibular FD was associated with higher rates of caries and malocclusion than were present in healthy patients. Furthermore, patients with FD did not require special dental management and were able to undergo routine dental care without an exacerbation of FD lesions.

Melatonin deficiency and fibrous dysplasia: might a relation exist?

Fibrous dysplasia of bone might be monostotic, polystotic, or occurs as a part of McCune–Albright syndrome and Jaffe–Lichtenstein syndrome. Activating mutations of GNAS1 gene was identified in patients with fibrous dysplasia. However, fibrous dysplasia might occur in the absence of these mutations and fibrous dysplastic tissue was produced in vitro by the effects of excess exogenous cAMP on human osteogenic cells. It was proved that the fibrous dysplastic tissue is deficient in bone sialoprotein. Melatonin deficiency might be hypothesized in syndromes associated with fibrous dysplasia or formation of fibrous dysplasia-like tissue. The receptor RZR/ROR is the nuclear receptor of melatonin and the human bone sialoprotein gene contains a RZR/ROR response element. It was supposed that binding of melatonin to its membrane receptors results in changes in the levels of activity of nuclear cAMP that lead to alteration of expression of bone sialoprotein. Also, melatonin deficiency might increase cAMP in bone through its effect on prostaglandins of the E group. Further, melatonin deficiency might explain precocious puberty in cases of McCune–Albright syndrome. We might hypothesize that melatonin deficiency might play a role in development of fibrous dysplasia in some cases.

Gene abnormality associated with resistance to parathyroid hormone

Pseudohypoparathyroidism (PHP) is characterized by PTH-resistant hypocalcemia and hyperphosphatemia. Patients with PHP-Ia exhibit Albright osteodystrophy and resistance to TSH and other hormones in addition to PTH. PHP-Ia is caused by heterozygous inactivating mutations in the GNAS1 gene which encodes Gsalpha protein. In PHP-Ib, resistance to PTH is confined to the renal tubules. Recent reports describe a paternally imprinted disorder in a region including the GNAS1 gene as the cause of PHP-Ib.

Pseudohypoparathyroidism: from bedside to bench and back.

Pseudohypoparathyroidism: from bedside to bench and back.