Basal ganglia calcification in hypoparathyroidism and pseudohypoparathyroidism: local and systemic metabolic mechanisms.

BACKGROUND: Hypoparathyroidism and pseudohypoparathyroidism are rare disorders of mineral metabolism which may be associated with soft tissue calcification in the basal ganglia in the brain, and occasionally the skin and other tissues. The basal ganglia are the most common sites of calcification in the central nervous system in these disorders, and were first associated with this manifestation in a report from the Mayo Clinic in 1939. The reasons why the basal ganglia are a common site of soft tissue calcification in these rare disorders has been a matter of investigation for many years. FINDINGS: Due to recent increased understanding of phosphate transport and new insights gained from mRNA expression in the basal ganglia, the pathophysiology of basal ganglia calcification (BGC) is now clearer. There is evidence that the absence of parathyroid hormone in hypoparathyroidism may play a direct role, but this is clearly not the case in pseudohypoparathyroidism, which is associated with increased parathyroid hormone levels. Maintaining the calcium/phosphorus ratio as close to normal as possible, and maintaining normal serum phosphate levels, may help mitigate the progression of BGC. There is no evidence of regression of BGC with conventional treatment, and long-term data with adjunctive or replacement therapy with parathyroid hormone or its analogues are not yet available. PURPOSE OF THE REVIEW: This review will focus on the pathophysiology of BGC in hypoparathyroidism and pseudohypoparathyroidism, and review the proposed pathophysiologic mechanisms, as well as the clinical implications of BGC on patient quality of life.

Manifestations of left ventricular dysfunction and arrhythmia in patients with chronic hypoparathyroidism and pseudohypoparathyroidism: a preliminary study.

BACKGROUND: Cardiac damage triggered by severe hypocalcemia is well known. However, the role of chronic hypoparathyroidism (HP) and pseudohypoparathyroidism (PHP) in cardiac health is still unclear. We investigated the effect of chronic HP and PHP on cardiac structure and conductive function in patients compiling with treatment. METHODS: The study included 18 patients with HP and eight with PHP aged 45.4 ± 15.4 and 22.1 ± 6.4 years, respectively with a previously regular follow-up. In addition, 26 age- and sex-matched healthy controls were included. General characteristics and biochemical indices were recorded. Cardiac function and structure were assessed by estimation of myocardial enzymes, B-type natriuretic peptide (BNP), and echocardiography. The 12-lead electrocardiogram and 24-h Holter electrocardiography were performed to evaluate the conductive function. RESULTS: Levels of serum calcium in HP and PHP were 2.05 ± 0.16 mmol/L and 2.25 ± 0.19 mmol/L, respectively. The levels of myocardial enzyme and BNP were within the normal range. Adjusting for age at evaluation and body mass index, all M-mode measurements, left ventricular mass (LVM), LVM index (LVMI) and relative wall thickness (RWT) were comparable between patients and controls. Prolongation of corrected QT (QTc) intervals occurred in 52.6% (10/19) of patients, and 6.7% (1/15) of patients manifested more than 100 episodes of supraventricular and ventricular extrasystoles, as well as supraventricular tachycardia. None of the above arrhythmias was related to a severe clinical event. CONCLUSIONS: From this pilot study, patients diagnosed with HP and PHP and well-controlled serum calcium levels manifested normal cardiac morphology and ventricular function, except for prolonged QTc intervals, and a small percentage of mild arrhythmias needing further investigation.

Impaired amygdala-based learning and decreased anxiety in a murine model of pseudohypoparathyroidism type 1A.

Pseudohypoparathyroidism type 1A (PHP1A) is a genetic disorder caused by maternally inherited mutations in the gene Gnas. PHP1A is characterized by multiple hormone impairment, early onset obesity and cognitive impairment. Animal models of PHP1A are needed to investigate the mechanism of cognitive impairment. In the present study we used the cre-lox murine model to investigate behavior and cognition in maternally vs. paternally inherited gnas mutations expressed in the central nervous system. We observed a behavioral phenotype of decreased anxiety and impaired amygdala-based learning in the PHP1A mutant mouse model though there was no difference in hippocampal based learning tasks. In the elevated zero maze and open field analysis in the locomotor activity chambers, mutant mice showed diminished anxiety/increased impulsivity which could correlate with the attention deficit phenotype of children with PHP1A. The mutant mice also demonstrated poorer motor strength on the inverted screen test. These findings mirror some clinical features of PHP1A though overall the murine phenotype was milder than expected.

[Albright's hereditary osteodystrophy: a case study]. / Ostéodystrophie héréditaire d'Albright: à propos d'une observation.

Albright's hereditary osteodystrophy is a rare disease, characterized by phosphocalcic balance abnormalities related to peripheral resistance to parathyroid hormone. It is an hereditary affection with autosomal dominant inheritance pattern caused by mutation in GNAS gene1. It combines specific morphotype, subcutaneous calcifications, bone and renal resistance to parathyroid hormone. We report a new case of Albright's hereditary osteodystrophy in a 9-month old infant followed up for significant hypocalcaemia which occurred at 10 days of life. The purpose of this study was to remind clinicians of the clinical, biological, genetic and therapeutic features of this disease.

Cardiovascular findings in patients with nonsurgical hypoparathyroidism and pseudohypoparathyroidism: A cohort study.

OBJECTIVE: As only sparse data are available on indices of cardiovascular health among patients with nonsurgical hypoparathyroidism (Ns-HypoPT) and pseudohypoparathyroidism (PHP), we aimed to compare the cardiovascular profile between these groups of patients. METHODS: A total of 56 patients with Ns-HypoPT and 30 with PHP were included and underwent a clinical examination including blood sampling and measurements of arterial stiffness, pulse wave velocity (PWV) and blood pressure (BP). Arterial stiffness and PWV were measured using AtCor SphygmoCor-XCEL (Atcor Medical Pty Ltd, Sydney, NSW, Australia). RESULTS: Patients with Ns-HypoPT had an average age of 47 ± 17 years (68% females) and PHP patients 36 ± 13 years (80% females). Over 70% in both groups were genetically screened. Groups did not differ in terms of a history of cardiovascular disease, smoking status, use of calcium and vitamin D supplements or treatment with cholesterol-lowering or antihypertensive drugs. Compared with Ns-HypoPT, PHP patients had significantly lower levels of high-density lipoproteins (HDL) cholesterol and average glucose from HbA1c (Pboth  = 0.01). PWV was significantly higher among patients with Ns-HypoPT (Pcrude  = 0.02), even after adjustment for mean arterial pressure, body mass index, age and gender (Padjusted  < 0.01). Heart rate was significantly higher in Ns-HypoPT compared with PHP (P = 0.03). Office BP and 24-hour ambulatory BP did not differ between groups (P > 0.05). CONCLUSION: Patients with Ns-HypoPT have compared with PHP a higher arterial stiffness and heart rate. This has been associated with an increased risk of cardiovascular disease. Our data suggest that resistance to PTH is present in the cardiovascular system in PHP.

[Implication in Paediatrics of the First International Consensus Statement for the Diagnosis and management of pseudohypoparathyroidism and related disorders]. / Implicaciones en pediatría del primer consenso internacional para el diagnóstico y asistencia a pacientes con pseudohipoparatiroidismo y enfermedades relacionadas.

Since Albright and co-workers described pseudohypoparathyroidism in 1942 as the combined presence of hypocalcaemia and hyperphosphataemia associated with the existence of tissue resistance to parathyroid hormone (PTH) action upon normal renal function, great advances have been made in the clinical and genetic profile of patients affected by this condition. Furthermore, not only have genetic bases of pseudohypoparathyroidism been unravelled, but also variants in other genes involved in the PTH/PTHrP signalling pathway through Gsα, have been identified as the cause of diseases that share clinical features with pseudohypoparathyroidism. In the paediatric setting, the first symptoms suggesting the impairment of this signalling pathway are the presence of subcutaneous ossifications, brachydactyly and/or early onset obesity, followed by the possible development of PTH resistance. This clinical suspicion should be confirmed by an accurate molecular diagnosis to allow for coordinated multidisciplinary clinical management. Among the features of this group of disorders, physicians should pay attention to evaluation of PTH and/or thyrotropin (TSH) resistance at diagnosis and throughout follow-up, as well as growth hormone deficiency, hypogonadism, skeletal deformities, dental impairment, obesity, insulin resistance, impaired glucose tolerance or type2 diabetes mellitus and hypertension, as well as ectopic ossifications (either subcutaneous or affecting deeper tissues) and impairment of neurocognitive development.

Pseudohypoparathyroidism.

Pseudohypoparathyroidism (PHP) refers to a heterogeneous group of uncommon, yet related metabolic disorders that are characterized by impaired activation of the Gsα/cAMP/PKA signaling pathway by parathyroid hormone (PTH) and other hormones that interact with Gsa-coupled receptors. Proximal renal tubular resistance to PTH and thus hypocalcemia and hyperphosphatemia, frequently in presence of brachydactyly, ectopic ossification, early-onset obesity, or short stature are common features of PHP. Registries and large cohorts of patients are needed to conduct clinical and genetic research, to improve the still limited knowledge regarding the underlying disease mechanisms, and allow the development of novel therapies.

Health-related quality of life in patients with nonsurgical hypoparathyroidism and pseudohypoparathyroidism.

OBJECTIVE: Nonsurgical hypoparathyroidism (NS-HypoPT) and pseudohypoparathyroidism (PHP) are rare diseases, with a prevalence of 2/100.000 and 1/100.000, respectively. Only few studies on Quality of Life (QoL) among patients with Ns-HypoPT and PHP are available. We aimed to investigate the QoL among patients with Ns-HypoPT and PHP including information about education. DESIGN: A cohort study with patients identified from a previously epidemiological study. PATIENTS: Fifty seven patients with Ns-HypoPT and 30 patients with PHP. MEASUREMENTS: The well-validated questionnaires SF-36v2 and WHO-5 Well Being Index. Results compared to norm-based material, disease-specific norm-based material and patients with postsurgical HypoPT RESULTS: SF36v2 showed a significantly reduced score in all eight subdomains in patients with NS-HypoPT compared with a norm-based population. PHP patients scored lower in five subdomains. Females were more affected than males. Compared with postsurgical HypoPT, Ns-HypoPT and PHP are compatible at most domains. At the domains Physical Function, Social Function and Mental Health, Ns-HypoPT and PHP patients scored significantly lower (Pall  < .05). At the Mental Component Score, patients with Ns-HypoPT had a lower score compared with postsurgical HypoPT (P < .01). The overall WHO-5 Well Being Index score was comparable between groups (P = .45). No differences were seen comparing patients with postsurgical HypoPT and Ns-HypoPT (P = .68) or postsurgical HypoPT and PHP (P = .67). A WHO-5 score below 28 indicates depression (NS-HypoPT=7; PHP=3, P = .71), whereas a score between 28-50 suggesting poor emotional well-being (NS-HypoPT=19; PHP=5, P = .13). The remaining patients scored above 50 suggesting well-being. CONCLUSION: QoL is impaired equally among patients with Ns-HypoPT and PHP.

Ossifications in Albright Hereditary Osteodystrophy: Role of Genotype, Inheritance, Sex, Age, Hormonal Status, and BMI.

Context: Albright hereditary osteodystrophy (AHO) is caused by heterozygous inactivating mutations in GNAS. Depending on the parental origin of the mutated allele, patients develop either pseudohypoparathyroidism type 1A (PHP1A), with multihormone resistance and severe obesity, or pseudopseudohypoparathyroidism (PPHP), without hormonal abnormalities or marked obesity. Subcutaneous ossifications (SCOs) are a source of substantial morbidity in both PHP1A and PPHP. Objective: This study investigated the previously undetermined prevalence of SCO formation in PHP1A vs PPHP as well as possible correlations with genotype, sex, age, hormonal resistance, and body mass index (BMI). Design: This study evaluated patients with AHO for SCOs by physical examination performed by one consistent physician over 16 years. Setting: Albright Clinic, Kennedy Krieger Institute; Institute for Clinical and Translational Research, Johns Hopkins Hospital; Albright Center, Connecticut Children's Medical Center. Patients: We evaluated 67 patients with AHO (49 with PHP1A, 18 with PPHP) with documented mutations in GNAS. Main Outcome Measures: Relationships of SCOs to genotype, sex, age, hormonal resistance, and BMI. Results: Forty-seven of 67 participants (70.1%) had SCOs. Patients with PHP1A and PPHP had similar prevalences and degrees of ossification formation. Patients with frameshift and nonsense mutations had much more extensive SCOs than those with missense mutations. Males were affected more than females. There was no correlation with hormonal status or BMI. Conclusions: There is a similar prevalence of SCOs in PHP1A and PPHP, and the extent of SCO formation correlates with the severity of the mutation. Males are affected more extensively than females, and the SCOs tend to worsen with age.

Current Nomenclature of Pseudohypoparathyroidism: Inactivating Parathyroid Hormone/Parathyroid Hormone-Related Protein Signaling Disorder.

Disorders related to parathyroid hormone (PTH) resistance and PTH signaling pathway impairment are historically classified under the term of pseudohypoparathyroidism (PHP). The disease was first described and named by Fuller Albright and colleagues in 1942. Albright hereditary osteodystrophy (AHO) is described as an associated clinical entity with PHP, characterized by brachydactyly, subcutaneous ossifications, round face, short stature and a stocky build. The classification of PHP is further divided into PHP-Ia, pseudo-PHP (pPHP), PHP-Ib, PHP-Ic and PHP-II according to the presence or absence of AHO, together with an in vivo response to exogenous PTH and the measurement of Gsα protein activity in peripheral erythrocyte membranes in vitro. However, PHP classification fails to differentiate all patients with different clinical and molecular findings for PHP subtypes and classification become more complicated with more recent molecular characterization and new forms having been identified. So far, new classifications have been established by the EuroPHP network to cover all disorders of the PTH receptor and its signaling pathway. Inactivating PTH/PTH-related protein signaling disorder (iPPSD) is the new name proposed for a group of these disorders and which can be further divided into subtypes - iPPSD1 to iPPSD6. These are termed, starting from PTH receptor inactivation mutation (Eiken and Blomstrand dysplasia) as iPPSD1, inactivating Gsα mutations (PHP-Ia, PHP-Ic and pPHP) as iPPSD2, loss of methylation of GNAS DMRs (PHP-Ib) as iPPSD3, PRKAR1A mutations (acrodysostosis type 1) as iPPSD4, PDE4D mutations (acrodysostosis type 2) as iPPSD5 and PDE3A mutations (autosomal dominant hypertension with brachydactyly) as iPPSD6. iPPSDx is reserved for unknown molecular defects and iPPSDn+1 for new molecular defects which are yet to be described. With these new classifications, the aim is to clarify the borders of each different subtype of disease and make the classification according to molecular pathology. The iPPSD group is designed to be expandable and new classifications will readily fit into it as necessary.

Gsα deficiency in the dorsomedial hypothalamus underlies obesity associated with Gsα mutations.

Gsα, encoded by Gnas, mediates hormone and neurotransmitter receptor-stimulated cAMP generation. Heterozygous Gsα-inactivating mutations lead to obesity in Albright hereditary osteodystrophy (AHO) patients, but only when the mutations occur on the maternal allele. This parent-of-origin effect is due to Gsα imprinting in the CNS, although the relevant CNS regions are unknown. We have now shown that mice with a Gnas gene deletion disrupting Gsα expression on the maternal allele, but not the paternal allele, in the dorsomedial nucleus of the hypothalamus (DMH) developed obesity and reduced energy expenditure without hyperphagia. Although maternal Gnas deletion impaired activation of brown adipose tissue (BAT) in mice, their responses to cold environment remained intact. Similar findings were observed in mice with DMH-specific deficiency of melanocortin MC4R receptors, which are known to activate Gsα. Our results show that Gsα imprinting in the DMH underlies the parent-of-origin metabolic phenotype that results from Gsα mutations and that DMH MC4R/Gsα signaling is important for regulation of energy expenditure and BAT activation, but not the metabolic response to cold.

Pseudohypoparathyroidism Type 1A-Subclinical Hypothyroidism and Rapid Weight Gain as Early Clinical Signs: A Clinical Review of 10 Cases.

OBJECTIVE: To evaluate the clinical signs and symptoms that would help clinicians to consider pseudohypoparathyroidism (PHP) type 1A as a diagnosis in a child. METHODS: A retrospective review of the medical records of children diagnosed by erythrocyte Gsα activity and/or GNAS1 gene study and followed-up for PHP type 1A. Clinical and biochemical parameters along with epidemiological data were extracted and analyzed. Weight gain during infancy and early childhood was calculated as change in weight standard deviation score (SDS), using the French growth reference values. An upward gain in weight ≥0.67 SDS during these periods was considered indicative of overweight and/or obesity. RESULTS: Ten cases of PHP type 1A were identified (mean age 41.1 months, range from 4 to 156 months). In children aged ≤2 years, the commonest clinical features were round lunar face, obesity (70%), and subcutaneous ossifications (60%). In older children, brachydactyly was present in 60% of cases. Seizures occurred in older children (3 cases). Short stature was common at all ages. Subclinical hypothyroidism was present in 70%, increased parathormone (PTH) in 83%, and hyperphosphatemia in 50%. Only one case presented with hypocalcemia. Erythrocyte Gsα activity tested in seven children was reduced; GNAS1 gene testing was performed in 9 children. Maternal transmission was the most common (six patients). In three other cases, the mutations were de novo, c.585delGACT in exon 8 (case 2) and c.344C>TP115L in exon 5 (cases 6&7). CONCLUSION: Based on our results, PHP type 1A should be considered in toddlers presenting with round face, rapid weight gain, subcutaneous ossifications, and subclinical hypothyroidism. In older children, moderate mental retardation, brachydactyly, afebrile seizures, short stature, and thyroid-stimulating hormone resistance are the most suggestive features.

A Girl With Beckwith-Wiedemann Syndrome and Pseudohypoparathyroidism Type 1B Due to Multiple Imprinting Defects.

CONTEXT: Several patients with Beckwith-Wiedemann Syndrome (BWS) with multiple imprinting defects found by genetic analysis have been described. However, only two cases have been described with both genetic and clinical signs and symptoms of multiple diseases caused by imprinting defects. CASE DESCRIPTION: The girl in this case presented at the age of 6 months with morbid obesity (body mass index, +7.5 SDS) and a large umbilical hernia. Genetic analysis showed BWS (hypomethylation of the KCNQ1OT1 gene). Calcium homeostasis was normal, and she had no signs of Albright hereditary osteodystrophy. At the age of 10 years, she presented with fatigue, and laboratory analyses showed marked hypocalcemia with signs of PTH resistance, but without evidence for Albright hereditary osteodystrophy, thus suggesting pseudohypoparathyroidism type 1B. Consistent with this diagnosis, methylation analysis of the GNAS complex revealed hypomethylation (about 20%) of the GNAS exon 1A, NESPAS, and GNASXL loci and hypermethylation (100% methylation) of the NESP locus. CONCLUSIONS: Imprinting defects at several different loci can occur in some patients, thus causing multiple different diseases. Symptoms of pseudohypoparathyroidism type 1B may be absent at diagnosis of BWS, yet prolonged subclinical hypocalcemia and/or hyperphosphatemia can have negative consequences (eg, intracerebral calcifications, myocardial dysfunction). We therefore suggest that patients with an imprinting disorder should be monitored for elevations in PTH, and epigenetic analysis of the GNAS complex locus should be considered.

Clinical insights by the presence of bipolar disorder in pseudohypoparathyroidism type 1A.

Pseudohypoparathyroidism type 1A and its association with bipolar disorder (BD) have never been reported so far. We report a new case with both clinical entities and discuss the potential pathophysiological mechanisms of this association (protein kinase A hypoactivation, parathyroid hormone, hypocalcemia, protein kinase C activation, vitamin D deficiency). In this patient, the correction of the underlying calcium and vitamin D deficiencies leads to a better BD outcome and lower dosage of psychopharmacological agents. The conclusions might be generalized for a better understanding and management of these conditions.

Increased Prevalence of Sleep Apnea in Children with Pseudohypoparathyroidism Type 1a.

BACKGROUND/AIMS: Pseudohypoparathyroidism type 1a (PHP1a) is a rare genetic disorder. This study aimed to determine the prevalence of sleep apnea in children with PHP1a. METHODS: Nineteen patients with PHP1a between the age of 2 and 21 years were enrolled prospectively using online advertisements. Parents completed a medical history and surveys to assess sleep behavior. Polysomnography records were obtained when available. In addition, 18 subjects were identified in a retrospective chart review of de-identified medical records with 2.3 million patient charts. RESULTS: Parents reported sleep disturbance (94%) and daytime somnolence (81%) in their children with PHP1a. In the retrospective chart review, 39% had a history of sleep apnea versus 8.8% of a similarly obese control group. In the combined analysis (n = 31), 52% had a history of snoring and 45% had a diagnosis of sleep apnea. Patients were obese with a mean BMI z-score of 2.20 ± 0.59. Patients with sleep apnea were significantly younger than those without a diagnosis (8.1 ± 5.4 vs. 12.8 ± 5.0 years, p = 0.02). CONCLUSIONS: Children with PHP1a have a 4.4-fold greater relative risk of sleep apnea than similarly obese children. Screening for sleep apnea in this population may be warranted to prevent adverse health outcomes.

Growth hormone deficiency in monozygotic twins with autosomal dominant pseudohypoparathyroidism type Ib.

Pseudohypoparathyroidism (PHP) is associated with compromised signal transductions via PTH receptor (PTH-R) and other G-protein-coupled receptors including GHRH-R. To date, while GH deficiency (GHD) has been reported in multiple patients with PHP-Ia caused by mutations on the maternally expressed GNAS coding regions and in two patients with sporadic form of PHP-Ib accompanied by broad methylation defects of maternally derived GNAS differentially methylated regions (DMRs), it has not been identified in a patient with an autosomal dominant form of PHP-Ib (AD-PHP-Ib) accompanied by an STX16 microdeletion and an isolated loss of methylation (LOM) at exon A/B-DMR. We studied 5 4/12-year-old monozygotic twins with short stature (both -3.4 SD) and GHD (peak GH values, <6.0 µg/L after arginine and clonidine stimulations). Molecular studies revealed maternally derived STX16 microdeletions and isolated LOMs at exon A/B-DMR in the twins, confirming the diagnosis of AD-PHP-Ib. GNAS mutation was not identified, and neither mutation nor copy number variation was detected in GH1, POU1F1, PROP1, GHRHR, LHX3, LHX4, and HESX1 in the twins. The results, in conjunction with the previous finding that GNAS shows maternal expression in the pituitary, suggest that GHD of the twins is primarily ascribed to compromised GHRH-R signaling caused by AD-PTH-Ib. Thus, resistance to multiple hormones including GHRH should be considered in AD-PHP-Ib.

Aspectos clínicos en dos casos de seudohipoparatiroidismo ( Ia y Ib) y estudio molecular del locus GNAS / Clinical features of two cases of pseudohypoparathyroidism ( I a and I b) and molecular analysis of GNAS

El seudohipoparatiroidismo (PHP) es una entidad rara, caracterizada por resistencia tisular a la hormona paratiroidea (PTH). Los 2 subtipos principales, PHP-Ia y PHP-Ib, son causados por alteraciones en el gen GNAS (20q13.3), que codifica para la proteína Gsα, esencial para la acción de la PTH y otras hormonas. El PHP-Ia se asocia a diversas alteraciones hormonales, osteodistrofia hereditaria de Albright (AHO) y actividad reducida de Gsα. Está causado por mutaciones inactivantes del gen GNAS. El PHP-Ib presenta resistencia aislada a la PTH, sin AHO y con actividad Gsα normal o levemente baja. Se asocia a defectos en la impronta de GNAS. Se presentan 2 casos con PHP-Ia y PHP-Ib, ahondando en su clínica y en el diagnóstico diferencial frente a afecciones similares (AU)

Pseudohypoparathyroidism (PHP) is a rare disorder, characterized by a tissue resistance to parathyroid hormone (PTH). The two main subtypes of PHP, PHPIa and PHPIb, are caused by alterations in the GNAS locus (20q13.3), which encodes the Gs protein, essential for the action of PTH and other hormones. PHP-Ia is associated with several hormone resistances, Albright hereditary osteodystrophy (AHO), and reduced Gsα activity. It is caused by inactivating mutations in the GNAS gene. PHPIb presents with isolated resistance to PTH, without AHO and with normal to low Gsα activity. It is related to imprinting defects in GNAS. Two unrelated cases of PHP-Ia and PHP-Ib are presented here, focusing on their clinical aspects and in the differential diagnosis with similar pathologies (AU)