Primary pigmented nodular adrenocortical disease (PPNAD) and pituitary adenoma in a boy with sporadic Carney complex due to a novel, de novo paternal PRKAR1A mutation (R96X)

The clinical characteristics and pathogenic variants of primary pigmented nodular adrenocortical disease in 210 patients: a systematic review

Aims

Primary pigmented nodular adrenocortical disease (PPNAD), as a rare kind of Cushing's syndrome, is frequently misdiagnosed. To get a better understanding of the disease, we analyzed the clinical characteristics and pathogenic variants of PPNAD.

Methods

Databases were searched, and the pathogenic variants and clinical manifestations of patients were summarized from the relevant articles.

Results

A total of 210 patients in 86 articles were enrolled with a median age of 22 and a female-to-male ratio of 2:1. Sixty-six (31.43%) patients were combined with Carney complex (CNC) and 94.29% were combined with osteoporosis/osteopenia. Among 151 patients who underwent genetic testing, 87.42% (132/151) had pathogenic variants. Six gene mutations (PRKAR1A, PDE11A, PRKACA, CTNNB1, PDE8B, and ARMC5) were detected in the patients. The most common mutation was PKAR1A, accounting for 79.47% (120/151). There was a significant correlation between PRKAR1A pathogenic variant and spotty skin pigmentation in CNC concurrent with PPNAD (p < 0.05). Among pregnant patients with PPNAD, those without surgical treatment and with bilateral adrenalectomy suffered from a high-risk perinatal period. However, patients with unilateral adrenalectomy presented a safe perinatal period.

Conclusions

For young patients with Cushing's syndrome, especially female patients with spotty skin pigmentation and osteoporosis/osteopenia, PPNAD should be considered. Unilateral adrenal resection may be considered as an option for women with fertility needs. In view of the difficulty of PPNAD diagnosis, genetic testing before surgery might be a reasonable option. Patients with PPNAD with spotty skin pigmentation should consider the PRKAR1A pathogenic variant and pay attention to CNC.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023416988.

Association between subclinical hyperthyroidism and a PRKAR1A gene variant in Carney complex patients: A case report and systematic review

BACKGROUND AND OBJECTIVES

It is currently controversial whether subclinical hyperthyroidism is associated with PRKAR1A gene variants. We describe a man with subclinical hyperthyroidism and a PRKAR1A gene variant who was diagnosed with Carney complex (CNC), and we performed a systematic review of published studies to assess the association between PRKAR1A gene variants and the risk of subclinical hyperthyroidism.

DESIGN AND METHODS

The PubMed, EMBASE, OVID, Science Direct, and gray literature electronic databases were searched for articles published from January 2002 to May 2021 using predefined keywords and inclusion and exclusion criteria. Data on thyroid function from selected studies were extracted and analyzed.

RESULTS

We identified a CNC patient with a subclinical hyperthyroidism phenotype combined with multiple components and genetic sequenced data. In a subsequent systematic review, twenty selected studies (14 case studies and 6 series studies) enrolling 23 individuals were included in the final analysis. The patient's thyroid function data were qualitative in 11 cases and quantitative in 12 cases. The prevalence of subclinical hyperthyroidism in the CNC patients with a PRKAR1A gene variant, including our patient, was markedly higher than that in the normal population (12.5% vs. 2%).

CONCLUSIONS

The findings of this systematic review provide helpful evidence that PRKAR1A gene variants and subclinical hyperthyroidism are related and suggest that subclinical hyperthyroidism may be a neglected phenotype of PRKAR1A gene variants and a novel component of CNC patients.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42021197655.

Deletions of the PRKAR1A locus at 17q24.2-q24.3 in Carney complex: genotype-phenotype correlations and implications for genetic testing

BACKGROUND

Carney complex (CNC) is a multiple neoplasia syndrome caused by PRKAR1A-inactivating mutations. One-third of the patients, however, have no detectable PRKAR1A coding sequence defects. Small deletions of the gene were previously reported in few patients, but large deletions of the chromosomal PRKAR1A locus have not been studied systematically in a large cohort of patients with CNC.

SETTING

A tertiary care referral center was the setting for analysis of an international cohort of patients with CNC.

METHODS

Methods included genome-wide array analysis followed by fluorescent in situ hybridization, mRNA, and other studies as well as a retrospective analysis of clinical information and phenotype-genotype correlation.

RESULTS

We detected 17q24.2-q24.3 deletions of varying size that included the PRKAR1A gene in 11 CNC patients (of 51 tested). Quantitative PCR showed that these patients had significantly lower PRKAR1A mRNA levels. Phenotype varied but was generally severe and included manifestations that are not commonly associated with CNC, presumably due to haploinsufficiency of other genes in addition to PRKAR1A.

CONCLUSIONS

A significant number (21.6%) of patients with CNC that are negative in currently available testing may have PRKAR1A haploinsufficiency due to genomic defects that are not detected by Sanger sequencing. Array-based studies are necessary for diagnostic confirmation of these defects and should be done in patients with unusual and severe phenotypes who are PRKAR1A mutation-negative.

Large deletions of the PRKAR1A gene in Carney complex

PURPOSE

Since the identification of PRKAR1A mutations in Carney complex, substitutions and small insertions/deletions have been found in approximately 70% of the patients. To date, no germ-line PRKAR1A deletion and/or insertion exceeded a few base pairs (up to 15). Although a few families map to chromosome 2, it is possible that current sequencing techniques do not detect larger gene changes in PRKAR1A -- mutation-negative individuals with Carney complex.

EXPERIMENTAL DESIGN

To screen for gross alterations of the PRKAR1A gene, we applied Southern hybridization analysis on 36 unrelated Carney complex patients who did not have small intragenic mutations or large aberrations in PRKAR1A, including the probands from two kindreds mapping to chromosome 2.

RESULTS

We found large PRKAR1A deletions in the germ-line of two patients with Carney complex, both sporadic cases; no changes were identified in the remaining patients, including the two chromosome-2-mapping families. In the first patient, the deletion is expected to lead to decreased PRKAR1A mRNA levels but no other effects on the protein; the molecular phenotype is predicted to be PRKAR1A haploinsufficiency, consistent with the majority of PRKAR1A mutations causing Carney complex. In the second patient, the deletion led to in-frame elimination of exon 3 and the expression of a shorter protein, lacking the primary site for interaction with the catalytic protein kinase A subunit. In vitro transfection studies of the mutant PRKAR1A showed impaired ability to bind cyclic AMP and activation of the protein kinase A enzyme. The patient bearing this mutation had a more-severe-than-average Carney complex phenotype that included the relatively rare psammomatous melanotic schwannoma.

CONCLUSIONS

Large PRKAR1A deletions may be responsible for Carney complex in patients that do not have PRKAR1A gene defects identifiable by sequencing. Preliminary data indicate that these patients may have a different phenotype especially if their defect results in an expressed, abnormal version of the PRKAR1A protein.

[Carney complex. Clinical, pathological and genetic features in two generations of a family]

Clinical symptoms of Carney complex occurred in two female members of one family (mother and daughter). In addition to the clinical symptoms, we describe the pathological findings in the adrenals (pigmented nodular hyperplasia of the adrenal cortex), heart (myxoma) and skin/soft tissues (superficial angiomyxomas). Genetic investigation revealed a mutation on the long arm of chromosome 17 in both patients; this mutation had previously been described only in Carney complex type 1. Unilateral adrenalectomy was performed in both these cases, 13 years ago and 7 months ago, respectively. Lifelong cardiac surveillance is mandatory to prevent death from embolism or arrhythmia.