Eric W. Glissmeyer

Pulmonary arterial hypertension (PAH) is clinically characterized by a sustained elevation in mean pulmonary artery pressure leading to significant morbidity and mortality. The disorder is typically sporadic, and in such cases the term idiopathic PAH (IPAH) is used. However, cases that occur within families (familial PAH (FPAH)) display similar clinical and histopathological features, suggesting a common etiology. Heterozygous mutations of a type II member of the TGF-beta cell signaling superfamily known as BMPR2 on chromosome 2q33 have been identified in many kindreds with FPAH, yet display both reduced penetrance and sex bias. This report presents the compilation of data for 144 distinct mutations that alter the coding sequence of the BMPR2 gene identified in 210 independent PAH subjects. This large data set characterizes the extent of sequence variation and reveals that the majority (71%) of mutations in FPAH and IPAH comprise nonsense, frameshift, and splice-site defects, and gene rearrangements. These predict premature termination of the transcript with likely loss through the process of nonsense-mediated decay (NMD). A total of 44 missense mutations were identified that substitute amino acid residues at highly conserved sites within recognized functional domains of the mature receptor. We assess this category of mutations in the context of their heterogeneous effects on cell signaling when assayed by in vitro cell-based systems. Disease-causing mutation hot-spots within BMPR2 are summarized. Taken together, these observations are likely to aid in the development of targeted mutation detection strategies relevant for patient management. Finally, we examine the age- and sex-dependent reduced penetrance of BMPR2 mutations by reviewing bmpr2 animal models and the requirement for additional genetic and/or environmental modifiers of disease. In conclusion, these data provide compelling genetic evidence that haploinsufficiency is the predominant molecular mechanism underlying disease predisposition, and support the concept of a critical threshold of signaling activity below which disease may be precipitated.

BACKGROUND: Vasoreactivity tests are fundamental in evaluating pulmonary arterial hypertension (PAH). Mutations of the transforming growth factor-beta type II receptor gene, BMPR2, predispose to the development of pulmonary hypertension and may alter the response to vasodilators. Previous investigations have not examined the relationship of BMPR2 mutations to vasoreactivity. METHODS AND RESULTS: We identified 133 consecutive unrelated patients with either idiopathic or familial PAH. Sixty-six patients were excluded because we lacked either DNA samples (n=18) or complete data from a vasoreactivity test (n=48). The remaining 67 patients were screened for BMPR2 DNA sequence variations, and specific variations were confirmed by gene sequencing. The vasoreactivity of patients with nonsynonymous BMPR2 variations was compared with that of patients without nonsynonymous BMPR2 variations. We found nonsynonymous BMPR2 variations in 27 of 67 patients with idiopathic (n=16 of 52) or familial (n=11 of 15) PAH. Vasoreactivity was identified in 3.7% of 27 patients with nonsynonymous BMPR2 variations and in 35% of 40 patients without nonsynonymous BMPR2 variations (P=0.003). Five of the 27 nonsynonymous variations occur commonly in healthy individuals. None of the remaining 22 patients with BMPR2 variations demonstrated vasoreactivity, and the analysis remained unchanged when we assumed that nonsynonymous BMPR2 variations were present in all 15 patients with familial PAH. CONCLUSIONS: Patients with familial or idiopathic PAH and nonsynonymous BMPR2 variations are unlikely to demonstrate vasoreactivity. Further trials are required to determine whether long-term therapy can be directed by tests for BMPR2 variations.

BACKGROUND: The effects of pulmonary arterial hypertension on cardiovascular and physical function are well documented. Limited information exists regarding the effects of pulmonary arterial hypertension on cognitive function despite patient reports of problems with memory and attention. Our primary purpose was to determine if a prospectively identified cohort of pulmonary arterial hypertension patients had cognitive sequelae. Our secondary purpose was to determine the relationships between cognitive sequelae and neuropsychological test scores with depression, anxiety, and quality of life. METHODS: Forty-six adults with pulmonary arterial hypertension underwent assessment of cognitive function, depression, anxiety, and quality of life using standardized neuropsychological tests and questionnaires. The patients' scores were compared to normal population data. Medical, affective, neuropsychological, and quality of life data for patients with and without cognitive sequelae were compared using analysis of variance, Chi-square, or Fisher exact tests for categorical data. Correlations assessed relationships between neuropsychological test scores, depression, anxiety, quality of life, and medical data. RESULTS: Cognitive sequelae occurred in 58% (27/46) of the pulmonary arterial hypertension patients. Patients with cognitive sequelae had worse verbal learning, delayed verbal memory, executive function, and fine motor scores compared to patients without cognitive sequelae. Twenty-six percent of patients had moderate to severe depression and 19% had moderate to severe anxiety. Depression, anxiety and quality of life were not different for patients with or without cognitive sequelae. Our patients had decreased quality of life, which was associated with worse working memory. CONCLUSION: Patients with pulmonary arterial hypertension have cognitive impairments, depression, anxiety, and decreased quality of life. Depression, anxiety, and quality of life were similar for patients with cognitive sequelae compared to those without cognitive sequelae. Decreased quality of life was associated with worse verbal and working memory. Clinicians should be aware of adverse brain related outcomes in PAH patients. Attention to proximal determinants and possible interventions to prevent or reduce cognitive and emotional morbidity and decreased quality of life are warranted and should be an emphasis in outcomes research.

OBJECTIVE: This study compares the performance of urine dipstick alone with urine microscopy and with both tests combined as a screen for urinary tract infection (UTI) in febrile infants aged 1 to 90 days. METHODS: We queried the Intermountain Healthcare data warehouse to identify febrile infants with urine dipstick, microscopy, and culture performed between 2004 and 2011. UTI was defined as >50 000 colony-forming units per milliliter of a urinary pathogen. We compared the performance of urine dipstick with unstained microscopy or both tests combined ("combined urinalysis") to identify UTI in infants aged 1 to 90 days. RESULTS: Of 13 030 febrile infants identified, 6394 (49%) had all tests performed and were included in the analysis. Of these, 770 (12%) had UTI. Urine culture results were positive within 24 hours in 83% of UTIs. The negative predictive value (NPV) was >98% for all tests. The combined urinalysis NPV was 99.2% (95% confidence interval: 99.1%-99.3%) and was significantly greater than the dipstick NPV of 98.7% (98.6%-98.8%). The dipstick positive predictive value was significantly greater than combined urinalysis (66.8% [66.2%-67.4%] vs 51.2% [50.6%-51.8%]). These data suggest 8 febrile infants would be predicted to have a false-positive combined urinalysis for every 1 infant with UTI initially missed by dipstick screening. CONCLUSIONS: Urine dipstick testing compares favorably with both microscopy and combined urinalysis in febrile infants aged 1 to 90 days. The urine dipstick test may be an adequate stand-alone screen for UTI in febrile infants while awaiting urine culture results.

RATIONALE: The bone morphogenetic receptor type II gene is the major genetic determinant for the inherited form of pulmonary arterial hypertension. However, deleterious mutations of this gene are not observed in the majority of subjects who develop the condition spontaneously and familial disease displays age- and sex-dependent penetrance, indicating the requirement for additional environmental and/or genetic modifiers for disease development. METHODS: We investigated polymorphic variation of the serotonin transporter gene, a biological candidate for predisposition to this vascular disorder. RESULTS: No significant evidence of association between alleles of the serotonin transporter gene and pulmonary hypertension was detected, nor did we observe a relationship with age of onset in familial and idiopathic disease. CONCLUSIONS: Variation of the serotonin transporter gene appears unlikely to confer significant susceptibility to pulmonary arterial hypertension. This study emphasizes the need for adequately powered cohorts for association analyses to identify not only genetic determinants of disease susceptibility but also inherited modifiers for disease development.