A pseudohypoparathyroidism type Ia patient with normocalcemia

Cutaneous Calcified Mass of Foot in Pseudohypoparathyoidism: Case Report

Soft tissue calcifications frequently appear on imaging studies, representing a prevalent but non-specific discovery, varying from a local reaction without clear cause to suggesting an underlying systemic condition. Because calcifications like these can arise from various causes, an accurate differential diagnosis is crucial. Differential diagnosis entails a methodical assessment of the patient, encompassing clinical presentation, medical history, radiological and pathological findings, and other pertinent factors. Through scrutiny of the patient's medical and trauma history, we can refine potential causes of calcification to vascular, metabolic, autoimmune, neoplastic, or traumatic origins. Furthermore, routine laboratory assessments, including serum levels of calcium, phosphorus, ionized calcium, vitamin D metabolites, and parathyroid hormone (PTH), aid in identifying metabolic etiologies. We describe a rare occurrence of osteoma cutis in a 15-year-old female patient with a history of pseudohypoparathyroidism (PHP) and Albright's hereditary osteodystrophy (AHO). The patient presented with a painful mass on the lateral side of her left foot. The diagnosis was based on medical history, laboratory tests, and imaging, leading to an excisional biopsy and complete pain relief post-surgery. Understanding such rare occurrences and related conditions is crucial for accurate diagnosis and management.

Clinical and Molecular Characteristics and Long-term Follow-up of Children With Pseudohypoparathyroidism Type IA

CONTEXT

Pseudohypoparathyroidism type IA (PHPIA) is a rare genetic disorder characterized by hormone resistance and a typical phenotype named Albright hereditary osteodystrophy. Unawareness of this rare disease leads to delays in diagnosis.

OBJECTIVE

The aims of this study were to describe the clinical and molecular characteristics of patients with genetically confirmed GNAS mutations and to evaluate their long-term outcomes.

METHODS

A retrospective search for all patients diagnosed with PHPIA in 2 referral centers in Israel was conducted.

RESULTS

Nine children (8 females) belonging to 6 families were included in the study. Five patients had GNAS missense mutations, 2 had deletions, and 2 had frameshift mutations. Four mutations were novel. Patients were referred at a mean age of 2.4 years due to congenital hypothyroidism (5 patients), short stature (2 patients), or obesity (2 patients), with a follow-up duration of up to 20 years. Early obesity was observed in the majority of patients. Elevated parathyroid hormone was documented at a mean age of 3 years; however, hypocalcemia became evident at a mean age of 5.9 years, about 3 years later. All subjects were diagnosed with mild to moderate mental retardation. Female adult height was very short (mean -2.5 SD) and 5 females had primary or secondary amenorrhea.

CONCLUSION

Long-term follow-up of newborns with a combination of congenital hypothyroidism, early-onset obesity, and minor dysmorphic features associated with PHPIA is warranted and molecular analysis is recommended since the complete clinical phenotype may develop a long time after initial presentation.

Genotype-phenotype correlations in pseudohypoparathyroidism type 1a patients: a systemic review

BACKGROUND

Pseudohypoparathyroidism type 1a (PHP1a) is a rare endocrine disease caused by partial defects of the α subunit of the stimulatory Guanosin triphosphate (GTP) binding protein (Gsα) resulting from maternal GNAS gene variation. The clinical manifestations are related to PTH resistance (hypocalcemia, hyperphosphatemia, and elevated serum intact PTH) in the presence or absence of multihormone resistance, and Albright's hereditary osteodystrophy (AHO).

OBJECTIVES

To summarize the molecular genetics results and clinical characteristics as well as to explore the correlations between them.

METHODS

Articles pertaining to PHP1a until May, 31, 2021 were reviewed and 527 patients with genetic diagnosis were included in the data analysis. The clinical characteristics and molecular genetics results of these patients were analyzed and compared to explore the correlations between them.

RESULTS

A total of 258 GNAS rare variants (RVs) were identified in 527 patients. The RVs were most commonly found in exons 1 and 7 (17.6% each), with frameshift (36.8%), and missense (31.3%) being the main types of RVs. The median age of onset was 5.0 years old. The most common clinical manifestations were elevation of PTH (86.7%) and AHO (87.5%). Thyroid stimulating hormone resistance was the most common hormone resistance (75.5%) other than PTH resistance. Patients with missense and in-frame RVs had lower incidence rates of the round face (P = .001) and subcutaneous ossifications (P < .001) than those with loss-of-function (non-sense, frameshift, splicing site variants, and large deletions) variants.

CONCLUSIONS

This study revealed the correlation between loss-of-function RVs with round faces and subcutaneous ossifications in PHP 1a patients. Further exploration of genotype-phenotype correlations through more standardized and prospective studies with long-term follow-up is necessary.

GNAS mutation is an unusual cause of primary adrenal insufficiency: a case report

Background

Primary adrenal insufficiency in children has non-specific and extensive clinical features, so the diagnosis of its etiology is complex and challenging. Although congenital adrenal hyperplasia is the most common cause, more and more other genetic causes have been identified. GNAS mutation is easily overlooked as a rare cause of primary adrenal insufficiency. Here we firstly report a neonatal case of primary adrenal insufficiency caused by GNAS mutation.

Case presentation

A boy was diagnosed with congenital hypothyroidism 10 days post-partum and treated immediately. He also had persistent hyperkalaemia and hyponatraemia with elevated adrenocorticotropic hormone. At 70 days after birth, he was transferred to our hospital on suspicion of congenital adrenal hyperplasia. Physical examination found no other abnormalities except for growth retardation. Laboratory examination revealed increased aldosterone and normal cortisol, 17-hydroxyprogesterone, and androstenedione levels. Abnormally elevated parathyroid hormone was accompanied by normal blood calcium. Genetic assessment found a de novo, heterozygous c.432 + 1G > A variant in GNAS.

Conclusions

We report this case to highlight that GNAS mutation is an unusual cause of primary adrenal insufficiency. The combination of primary hypothyroidism and /or pseudohypoparathyroidism will provide diagnostic clues to this condition.

Pseudohypoparathyroidism Type 1A with Normocalcaemia, due to the Novel C.389A&gt;G Variant of Exon 5 of the Guanine Nucleotide-Binding Protein, α-Stimulating Gene

Pseudohypoparathyroidism type 1A (PHP1A) is a rare disease caused by molecular defects in the maternally-inherited allele of the guanine nucleotide-binding protein, α-stimulating (GNAS) gene. The GNAS gene encodes the stimulatory G-protein α-subunit that regulates production of the second messenger cyclic adenosine monophosphate. Heterozygous inactivating mutations in these specific loci are responsible for a spectrum of phenotypic characteristics of the disease, including clinical features of the Albright’s hereditary osteodystrophy, due to resistance to parathyroid hormone (PTH). We report a case of PHP1A and explore the underlying novel point mutation of the GNAS gene that leads to an atypical PHP1A phenotype. A male patient with a round face, short stature, and brachydactyly accompanied by normocalcaemia and mild PTH resistance consulted at our center. The GNAS encoding region from the patient and both of his parents were amplified and sequenced directly in a sample of peripheral blood leukocytes. A novel c.389A>G point mutation in exon 5 of the GNAS gene, resulting in a p.Tyr130Cys peptidic chain change of the Gsα protein, detected in the proband, in heterozygous state. Sequencing of the GNAS gene from his parents did not reveal the c.389A>G mutation, confirming a de novo proband genotype. The maternal origin of the affected GNAS allele, along with mild PTH resistance, confirmed the PHP1A diagnosis. PHP1A, caused by inactivating GNAS mutations, presents a range of complex clinical phenotypes. The novel c.389A>G GNAS mutation presented in this case expands the spectrum of known PHP1A molecular defects and describes the associated phenotype.

Identification of a novel GNAS mutation in a case of pseudohypoparathyroidism type 1A with normocalcemia

BACKGROUND

Pseudohypoparathyroidism type 1A (PHP1A) is a rare genetic disease primarily characterized by resistance to parathyroid hormone along with hormonal resistance and other features of Albright hereditary osteodystrophy (AHO). It is caused by heterozygous inactivating mutations in the maternal allele of the GNAS gene, which encodes the stimulatory G-protein alpha subunit (Gsα) and regulates production of the second messenger cyclic AMP (cAMP). Herein, we report a case of of PHP1A with atypical clinical manifestations (oligomenorrhea, subclinical hypothyroidism, and normocalcemia) and explore the underlying genetic cause in this patient.

METHODS

Blood samples were collected from the patient, her family members, and 100 healthy controls. The 13 exons and flanking splice sites of the GNAS gene were amplified by PCR and sequenced. To further assess whether the novel mutation resulted in gain or loss of function of Gsα, we examined the level of cAMP activity associated with this mutation through in vitro functional studies by introducing the target mutation into a human GNAS plasmid.

RESULTS

A novel heterozygous c.715A > G (p.N239D) mutation in exon 9 of the GNAS gene was identified in the patient. This mutation was also found in her mother, who was diagnosed with pseudopseudohypoparathyroidism. An in vitro cAMP assay showed a significant decrease in PTH-induced cAMP production in cells transfected with the mutant plasmid, compared to that in the wild-type control cells (P < 0.01), which was consistent with loss of Gsa activity.

CONCLUSION

We identified a novel GNAS mutation that altered Gsα function, which furthers our understanding of the pathogenesis of this disease. Screening for GNAS mutations should be considered in suspected cases of PHP1A even if the classical signs are not present.

Pseudohypoparathyroidism vs. tricho-rhino-phalangeal syndrome: patient reclassification

OBJECTIVES

Given that tricho-rhino-phalangeal syndrome (TRPS) and pseudohypoparathyroidism/pseudopseudohypoparathyroidism (PHP/PPHP) are very rare monogenic disorders that share some features (distinctive facies, short stature, brachydactyly and, in some patients, intellectual disability) that lead to their misdiagnosis in some cases, our objective was to identify clinical, biochemical or radiological signs that could help to distinguish these two syndromes.

METHODS AND RESULTS

We report on two cases, which were referred to the Endocrinology and Pediatric Endocrinology Services for obesity. Clinical evaluation initially suggested the diagnosis of PHP-Ia [phenotype suggestive of Albright hereditary osteodystrophy (AHO) with parathyroid hormone (PTH) resistance] and PPHP (phenotype resembling AHO, without PTH resistance), but (epi)genetic analysis of the GNAS locus ruled out the suspected diagnosis. Further clinical re-evaluation prompted us to suspect TRPS, and this was confirmed genetically.

CONCLUSION

TRPS was mistakenly identified as PHP/PPHP because of the coexistence of obesity and brachydactyly, with PTH resistance in one of the cases. Specific traits such as sparse scalp hair and a pear-shaped nose, present in both cases, can be considered pathognomonic signs of TRPS, which could help us to reach a correct diagnosis.

Endocrine profile and phenotype-(epi)genotype correlation in Spanish patients with pseudohypoparathyroidism

CONTEXT

Recent advances in genetics and epigenetics have revealed an overlap between molecular and clinical features of pseudohypoparathyroidism (PHP) subtypes, broadening the previous spectrum of PHP genotype-phenotype correlations and indicating limitations of the current classification of the disease.

OBJECTIVES

The aim of the study was to screen patients with clinical diagnoses of PHP type I or pseudo-PHP for underlying molecular defects and explore possible correlations between molecular findings and clinical features.

PATIENTS AND METHODS

We investigated the GNAS locus at the molecular level in 72 affected patients (46 women and 26 men) from 56 nonrelated families. Clinical data were obtained for 63 of these patients (38 women and 25 men).

RESULTS

The molecular analysis showed that 35 patients carried structural mutations, 32 had loss of methylation, and 2 had a 2q37 deletion but did not reveal any (epi)mutation for 3 patients. Comparing these results and the clinical data, we observed that a younger age at diagnosis was associated with structural defects at the GNAS gene and epigenetic defects with a diagnosis later in life (9.19 ± 1.64 vs 24.57 ± 2.28 years, P < .0001).

CONCLUSIONS

This first global review of PHP in Spain highlights the importance of a detailed clinical and genetic study of each patient and the integrated analysis of the findings from the two approaches. It may also help geneticists and clinicians to raise the suspicion of PHP earlier, reach more accurate diagnoses, and provide patients with PHP and their families with useful genetic information and counseling, thereby improving outcomes and quality of life.

Bariatric surgery in an obese patient with Albright hereditary osteodystrophy: a case report

Introduction

We report for the first time the case of a patient with Albright hereditary osteodystrophy and pseudopseudohypoparathyroidism who underwent a Roux-en-Y gastric bypass.

Case presentation

A 26-year-old obese Caucasian woman with Albright hereditary osteodystrophy with pseudopseudohypoparathyroidism (heterozygous mutation (L272F) in GNAS1 exon 10 on molecular analysis) was treated with gastric bypass. She had the classical features of Albright hereditary osteodystrophy: short stature (138cm), obesity (body mass index 49.5kg/m2), bilateral shortening of the fourth and fifth metacarpals, short neck, round and wide face with bombed front and small eyes. Before the gastric bypass was performed, biochemical determination revealed a slightly low serum calcium level (2.09mmol/L; normal range 2.1 to 2.5mmol/l), and an elevated parathyroid hormone level (87ng/L; normal range 10 to 70ng/L) associated with low vitamin D level (19μg/L; normal range 30 to 50μg/L). Vitamin D supplementation was prescribed before surgery. After the Roux-en-Y gastric bypass, she achieved a progressive substantial weight loss, from 94kg (body mass index 49.5kg/m2) to 49kg (body mass index 25.9kg/m2) in one year. Her weight then stabilized at 50kg (body mass index 26kg/m2) during our three years of follow-up. Before the operation and every three months after it, she was screened for nutritional deficiencies, and serum markers of bone turnover and renal function were monitored. Considering the deficiencies in zinc, magnesium, calcium, vitamin D and vitamin B12, appropriate supplementation was prescribed. Before and two years after the Roux-en-Y gastric bypass, a dual-energy X-ray absorptiometry assessment of bone density was performed that showed no changes on her lumbar column (0.882g/cm² and both T-score and Z-score of −1.5 standard deviation). In addition, bone microarchitecture with a measurement of her trabecular bone score was found to be normal.

Conclusion

This is the first case of Roux-en-Y gastric bypass described in a patient with pseudopseudohypoparathyroidism showing that such a procedure seems to be safe in obese patients with Albright hereditary osteodystrophy and pseudopseudohypoparathyroidism if appropriately followed up. As obesity is a prominent feature of Albright hereditary osteodystrophy, such patients might seek bariatric surgery. After a Roux-en-Y gastric bypass, patients with Albright hereditary osteodystrophy associated with pseudopseudohypoparathyroidism need long-term follow-up on nutritional and metabolic issues.

A novel GNAS mutation in an infant boy with pseudohypoparathyroidism type Ia and normal serum calcium and phosphate levels

The objective of this study was to describe a new mutation in GNAS in a family with pseudohypoparathyroidism type Ia (PHP Ia), a rare osteometabolic disease. An 8-month-old boy was seen by an Endocrinologist due to obesity and low growth velocity. Noteworthy, his mother exhibited typical Albright hereditary osteodystrophy (AHO) phenotype. The clinical diagnosis of PHP Ia was suspected. The GNAS coding region from mother and son was amplified and directly sequenced. A novel heterozygous missense mutation (c.673T>C) was identified in exon 5 in both patients. In this family, the mother's clinical picture was the clue for the son's diagnosis. Molecular analysis of GNAS confirmed the diagnosis of PHP Ia in both patients and the child's early diagnosis was possible. Moreover, this novel missense substitution expands the spectrum of GNAS mutations associated with this disorder and allows for genetic counseling of this family.

Boy with pseudohypoparathyroidism type 1a caused by GNAS gene mutation (deltaN377), Crouzon-like craniosynostosis, and severe trauma-induced bleeding

We report on a 6-month-old boy with craniosynostosis, pseudohypoparathyroidism type 1a (PHP1A), and a GNAS gene mutation. He had synostoses of the coronal, frontal, and sagittal sutures, brachyturricephaly, and hydrocephaly. He also had congenital hypothyroidism, round face, full cheeks, shortness of limbs, mild developmental delay, and muscular hypotonia. Because of progressive hydrocephaly, the synostosis was corrected surgically but circulatory decompensation led to disseminated intravascular coagulation and cerebral infarctions. Our patient died 8 days later. Postmortem molecular studies of GNAS, the gene for guanine nucleotide-binding protein, alpha-stimulating activity polypeptide (gene for PHP1A), identified a de novo heterozygous 3 bp in frame deletion predicting a deletion of the asparagine residue at position 377 (deltaN377). This is the second report of this mutation. Results of molecular studies of craniosynostosis genes (FGFR2, FGFR3) and of numerous genetic variants predisposing to bleeding disorders were normal. We question whether craniosynostosis and trauma-induced bleeding disorder may be manifestations of PHP1A, or if our patient had two or three different congenital disorders.

A novel mutation causing pseudohypoparathyroidism 1A with congenital hypothyroidism and osteoma cutis

Various inactivating mutations in guanine nucleotide-binding protein, alpha-stimulating activity polypeptide1 (GNAS1) gene have been described with poor phenotype correlation. Pseudohypoparathyroidism type 1a (PHP1a) results from an inactivating mutation in the GNAS1 gene. Hormone resistance occurs not only to parathyroid hormone (PTH), but typically also to other hormones which signal via G protein coupled receptors including thyroid stimulating hormone (TSH), gonadotropins, and growth hormone releasing hormone. In addition, the phenotype of Albright hereditary osteodystrophy (AHO) is observed, which may include short stature, round facies, brachydactyly, obesity, ectopic soft tissue or dermal ossification (osteoma cutis) and psychomotor retardation with variable expression. We present a 2-year-old boy with PHP 1A who initially presented at age 3 weeks with congenital hypothyroidism. By 17 months of age, he manifested osteoma cutis, psychomotor retardation, obesity, brachydactyly and resistance to PTH with normocalcemia and mild hyperphosphatemia. Genetic analysis revealed a novel mutation in exon 13 of GNAS1 in our patient. This mutation, c.1100_1101insA, resulted in a frameshift and premature truncation of bases downstream. This mutation was also found in the mother of this patient who was also noted to have short stature, obesity, brachydactyly and non progressive osteoma cutis, but no hormone resistance.We report a novel heterozygous mutation causing PHP1A with PTH and TSH resistance and AHO which has not been described previously. PHP1A is also a rare presentation of congenital hypothyroidism.

Cutaneous and superficial soft tissue lesions associated with Albright hereditary osteodystrophy: clinicopathological and molecular genetic study of 4 cases, including a novel mutation of the GNAS gene

Albright hereditary osteodystrophy is a rare syndrome, in which cutaneous and superficial soft tissue lesions traditionally include osteomas and calcifications. We report 4 patients from 2 families affected with Albright hereditary osteodystrophy and demonstrate that the spectrum of these cutaneous and soft tissue lesions is broader than is usually defined in the literature. In addition to osteomas in the dermis and subcutis, including so-called plaque-like osteoma, we identified the following lesions: calcifying aponeurotic fibroma-like lesion, calcinosis circumscripta-like lesion, and unusual nevi with osteoid and/or peculiar intranuclear pseudoinclusions. One osteoma and the calcifying aponeurotic fibroma-like lesion were analyzed by HUMARA and proved to be clonal. In a family, a novel mutation in the GNAS gene was also identified.