Novel variants in TNRC6B cause global developmental delay with speech and behavioral abnormalities, short stature, low body weight, café-au-lait spots, and metabolic abnormality.

BACKGROUND: TNRC6B deficiency syndrome, also known as global developmental delay with speech and behavioral abnormalities (MIM 619243), is a rare autosomal dominant genetic disease mainly characterized by facial dysmorphism, developmental delay/intellectual disability (DD/ID), speech and language delay, fine and motor delay, attention deficit and hyperactivity disorder (ADHD), and variable behavioral abnormalities. It is caused by heterozygous variant in the TNRC6B gene (NM_001162501.2, MIM 610740), which encodes the trinucleotide repeat-containing adaptor 6B protein. METHODS: In this study, two Chinese patients with TNRC6B deficiency syndrome were recruited, and genomic DNA extraction from peripheral blood leukocytes of these parents and their family members was extracted for whole-exome sequencing and Sanger sequencing. RESULTS: Here, we report two unrelated Chinese patients diagnosed with TNRC6B deficiency syndrome caused by novel de novo likely pathogenic or pathogenic TNRC6B variants c.335C>T (p.Pro112Leu) and c.1632delC (p.Leu546fs*63), which expands the genetic spectrum of TNRC6B deficiency syndrome. The clinical features of the patients were DD/ID, delayed speech, ADHD, behavioral abnormalities, short stature, low body weight, café-au-lait spots, metabolic abnormalities, and facial dysmorphism including coarse facial features, sparse hair, frontal bossing, hypertelorism, amblyopia, strabismus, and downslanted palpebral fissures, which expands the phenotype spectrum associated with TNRC6B deficiency syndrome. CONCLUSION: This study expands the genotypic and phenotypic spectrum of TNRC6B deficiency syndrome. Our findings indicate that patients with TNRC6B deficiency syndrome should be monitored for growth and metabolic problems and therapeutic strategies should be developed to address these problems. Our report also suggests the clinical diversity of TNRC6B deficiency syndrome.

[Research progress on the pathogenic mechanisms, diagnosis and treatment of McCune-Albright syndrome].

McCune-Albright syndrome is a rare chimeric disorder due to mutations in the postzygotic GNAS gene. It belongs to the group of guanine nucleotide-binding protein diseases, affecting a wide range of individuals. It is characterized by fibrous dysplasia, café-au-lait skin macules, and precocious puberty with other variable clinical manifestations. At present, there are difficulties in the molecular diagnosis of McCune-Albright syndrome, and there is a lack of effective clinical treatments to halt or reverse the course and regression of the disease. This article summarizes the clinical manifestations, diagnosis, pathogenic molecular mechanisms, treatment and relevant fertility guidelines of McCune-Albright syndrome, with a view to further research and therapy of McCune-Albright syndrome.

The 730 nm picosecond titanium sapphire laser for treatment of café-au-lait macules in all skin types.

OBJECTIVES: Café-au-lait macules (CALM) are benign birthmarks presenting as uniformly pigmented, well demarcated, brown patches that can be distressing to patients, especially when located in cosmetically sensitive areas. As with all pigmentary lesions in skin of color patients, CALMs have been particularly challenging to treat. Here we present the first case series characterizing treatment parameters and clinical outcomes utilizing the 730-nm picosecond titanium sapphire laser for the treatment of CALMs. This device provides an additional safe and effective treatment option for these challenging cases. METHODS: We performed a retrospective review of patients treated at a single institution between April 2021 and December 2023. Clinical photographs were graded by 3 outside board-certified dermatologists using a 5-point visual analog scale. RESULTS: Fourteen patients (age range: 10 months-66 years, mean age: 27.4 years, Fitzpatrick skin types II-VI) were treated for CALM on the face (11) or body (3). On average, patients received 4.3 treatments, with treatment intervals ranging from 4 to 40 weeks. Treatment remains ongoing with the 730-nm picosecond laser for eight patients. Overall, patients were rated to have a mean improvement of 26%-50%. Two patients (FST III and VI) achieved 100% clearance after 4-5 treatment sessions. Our study included four patients whose CALM were of the smooth bordered "coast of California" subtype, three of whom had a mean improvement rating of only 1%-25%. The fourth patient had near complete resolution. Follow up for these patients has ranged from 6 weeks to 1.5 years. Of the patients treated, one patient experienced transient post-inflammatory hyperpigmentation and another transient post-inflammatory hypopigmentation, while a third patient experienced mild persistent guttate hypopigmentation. Three patients experienced partial recurrence indicating that maintenance treatments may be needed in some patients. CONCLUSION: The 730-nm picosecond titanium sapphire laser is a safe and efficacious treatment option, in the right morphologic setting, to improve the cosmetic appearance of CALMs in a wide range of ages and skin types. To our knowledge, this is the first reported treatment of CALMs with picosecond lasers in FST V and VI patients. Our study also supports prior studies which have found that CALM with smooth-bordered "coast of California" morphology have a poor response to laser therapy as compared to those with jagged or ill-defined bordered "coast of Maine" morphology.

Treatment With Selumetinib for Café-au-Lait Macules and Plexiform Neurofibroma in Pediatric Patients With Neurofibromatosis Type 1.

This case report describes 4 patients with a rare autosomal dominant multisystem disorder resulting from NF1 variants that leads to café-au-lait macules and neurofibromas.

Genetically confirmed coexistence of neurofibromatosis type 1 and Cherubism in a pediatric patient.

BACKGROUND: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder typified by various combination of numerous Café-au-lait macules, cutaneous and plexiform neurofibromas, freckling of inguinal or axillary region, optic glioma, Lisch nodules and osseous lesions. Cherubism is a rare genetic syndrome described by progressive swelling of the lower and/or upper jaw due to replacement of bone by fibrous connective tissue. Patients are reported in the literature with NF1 and cherubism-like phenotype due to the NF1 osseous lesions in the jaws. The purpose of this case report is the description of a young male genetically diagnosed with both NF1 and cherubism. METHODS AND RESULTS: A 9 years and six month old patient with clinical findings of NF1 and cherubism in whom both diseases were genetically confirmed, is presented. The patient was evaluated by a pediatrician, a pediatric endocrinologist, an ophthalmologist, and an oral and maxillofacial surgeon. A laboratory and hormonal screening, a histological examination, a chest X-ray, a magnetic resonance imaging (MRI) of the orbit and a digital panoramic radiography were performed. Genetic testing applying Whole Exome Sequencing was conducted. CONCLUSIONS: A novel and an already reported pathogenic variants were detected in NF1 and SH3BP2 genes, respectively. This is the first described patient with coexistence of NF1 and cherubism. The contribution of Next Generation Sequencing (NGS) in gene variant identification as well as the importance of close collaboration between laboratory scientists and clinicians, is highlighted. Both are essential for optimizing the diagnostic approach of patients with a complex phenotype.

Reflectance confocal microscopy as a complementary diagnostic tool for greyish-brown dermatoses in children.

Mastocytosis, lichen planus pigmentosus (LPP), fixed drug eruption (FDE) and café-au-lait macules (CALM) have a similar appearance, often lead to misdiagnosis and missed diagnoses. At the outpatient clinic at Tianjin Children's Hospital in 21 patients with mastocytosis, 18 with LPP, 11 with FDE and 12 with CALM we evaluated the characteristics and distinguishing features of their dermatoses using reflectance confocal microscopy (RCM). In mastocytosis, the dermal papillary rings generally had a significantly increased bright refractive index and the superficial dermis was filled with moderate refractive flocculent material. In LPP, the dermal papillary rings were absent and numerous different-sized cellular structures were densely distributed in the superficial dermis. In FDE, the dermal papillary rings were intact with a significantly increased bright refractive index. In CALM, normal dermal papillary rings were detected with a uniformly slightly increased refractive index and no obvious abnormality in the superficial dermis. RCM allows for real-time visualization of the major key diagnostic and distinguishing features of four greyish-brown dermatoses in children.

Clinical signs and genetic evaluation of patients with neurofibromatosis type 1 with and without optic pathway gliomas in a center in Turkey.

PURPOSE: Optic pathway gliomas (OPGs) occur in 15% of patients with neurofibromatosis type 1 (NF1). Their location renders biopsy or surgical resection difficult because of the risk of vision loss. Therefore, only a few NF1-OPGs have been used for tissue diagnosis, and only a few analyses have been published on the molecular changes that drive tumorigenesis. METHODS: Due to this reason, we evaluated 305 NF1 patients, 34 with OPG and 271 without OPG for germ line mutations. All subjects underwent clinical examination and DNA analysis of NF1, confirming the diagnosis of NF1. RESULTS: Clinically, the group with OPG had a significantly higher incidence of bone dysplasia (P < 0.001) and more café-au-lait spots (P = 0.001) compared to those in the group without OPG. The frequency of Lisch nodules was on the borderline of statistical significance (P = 0.058), whereas the frequency of neurofibromas did not differ significantly (cutaneous, P = 0.64; plexiform, P = 0.44). Individuals with OPG mostly had mutations in the first one-third of the NF1 gene compared with that in patients who did not have OPG. Some identical mutations were detected in unrelated families with NF1-OPG. CONCLUSION: The observation of certain phenotypic features and the correlation between genotype and phenotype might help to determine the risk of developing OPG with NF1.

Pathogenesis and treatment of a giant occipital bone defect with meningoencephalocele in an NF1 child: case report and review of the literature.

Autosomal dominantly inherited neurofibromatosis type I (NF1) is a systemic disorder caused by a mutation of a gene on chromosome 17q11.2 and characterized by multiple café-au-lait spots, lentiginous macules, Lisch nodules of the iris, and tumors of the nervous system. Bony manifestations such as scoliosis, dysplasia of the greater sphenoidal wing, tibial pseudoarthrosis, short stature, and macrocephaly have been reported in approximately 50% of patients. However, calvarial bone defects are rare. After screening 324 articles, 23 cases (12 adult and 11 pediatric patients) of occipital bone defects in NF1 patients were selected. All patients had a single/multiple bone defect over the lambdoid suture. Adjacent benign plexiform neurofibromas were observed in 14 patients (60.8%, 7 adults and 7 children); one adult patient was diagnosed with neurofibrosarcoma. Meningoencephalocele over the occipital defect was noted in 8 cases (34.78%, all adults). Cranioplasty was performed in only 17.39% of patients. Histologic examination was performed in 7 of the 15 patients with associated neurofibromas/neurofibrosarcomas. Biopsy of the bone margins surrounding the defect was performed in only one case. Pathologic examination of the herniated parieto-occipital or cerebellar tissue was not performed in any of the patients studied. We report the case of a 9-year-old girl with NF1 and a significant occipital bone defect and performed a systematic review of the relevant literature to highlight the challenges in treating this condition and to investigate the underlying mechanisms contributing to bone defects or dysplasia in NF1.

Neurofibroma: Case Series with Clinical Features and Recommendations.

Neurofibroma is an autosomal benign disorder. It can be localized, diffuse or invasive like plexiform neurofibroma that involves the nerves, muscle, tissues, skeleton. It represents itself as a destructive variant of neurofibroma, mostly present as orbital or periorbital neurofibroma or may be associated with autosomal dominant disease. Clinical diagnosis of neurofibromatosis (NF) according to National Institutes of Health (NIH) criteria should have more than two of the seven features including lisch nodules, cafe'- au-lait spots, plexiform neurofibroma, optic glioma, freckling, first degree relative with NF or dysplasia of cortical bones. However, proper early diagnosis is still crucial due to its various presentation such as cheek mass, painless swelling on skin, chalazion, intratracheal tumor, genital swelling or ptosis. It is reported that neurofibroma often represents as ocular or facial swelling. Here we are presenting features of neurofibroma of eight cases of patients from Civil Hospital, Karachi. These cases had main complain of overhanging skin mass mainly on orbital or periorbital region that damage the area and with poor daily activities. Multiple nodules on face and body along with them Cafe'-au-lait spots and lisch nodules were main signs. While, other signs i.e. ptosis, pterygium, telecanthus and muddy discoloration of conjunctiva need further evaluation for correlation with neurofibromatosis. Debulking surgery was planned for most of the cases but the huge disfigurement caused by overhanging skin mass and nodules made it a challenge for plastic surgeons to provide good outcomes with minimum damage. Keywords: neurofibroma; lisch nodules; ptosis; Cafe'-au-lait spot; periorbital; overhanging skin.

[McCune-Albright syndrome: a case report and literature review]. / Syndrome de McCune-Albright : à propos d'un cas et revue de la littérature.

McCune-Albright syndrome is an inherited disease characterized by the association of fibrous dystrophy of bone, café-au-lait skin spots and precocious puberty revealing endocrine hyperactivity. Genetically, this disease is due to a mutation of the Gs protein responsible for activation of adenylate cyclase with excessive production of cAMP. The particular morphology of café-au-lait spots should suggest early diagnosis. Its treatment depends on the endocrinopathy from which the patient suffers and the extent of the fibrous dysplasia. Bisphosphonates have proven their effectiveness on bone pain and the limitation of fibrous dysplasia. Surgery retains its place in complicated forms. We report a rare case of McCune-Albright syndrome complicated by a femur fracture in a 12-year-old girl and we discuss the clinical and paraclinical characteristics of this pathological entity.

[Analysis of clinical features and variants of NF1 gene in 12 patients with Neurofibromatosis type 1].

OBJECTIVE: To explore the types of NF1 gene variants and clinical characteristics among patients with Neurofibromatosis type I (NF1). METHODS: Clinical data of 12 patients diagnosed at Ningbo Women and Children's Hospital between December 2019 and May 2022 were retrospectively analyzed. The probands and their family members were subjected to high-throughput sequencing, and candidate variants were verified by Sanger sequencing and chromosome microarray analysis. RESULTS: The 12 patients had ranged from 4 months to 27 years old, with a male-to-female ratio of 2 : 1. Cafè-au-lait spots were found in all patients. 83.3% of them also had axillary and/or inguinal freckling, 58.3% had neurofibromas, and 16.7% had congenital pseudarthrosis of the tibia. Five types of NF1 gene variants were identified in the patients, including 5 nonsense variants, 4 frameshift variants, 1 missense variant, 1 splice variant, 1 large deletion involving the whole gene. Six patients were found to harbor de novo variants, 2 had inherited the variants from their parents, and 4 were not verified for their parental origin. The c.3379del (p.Thr1127Glnfs*15) and c.6628_6629del (p.Glu2210Thrfs*10) variants were unreported in literature and databases. CONCLUSION: Most NF1 patients may present with Cafè-au-lait spots initially and are due to pathogenic variant of the NF1 gene. High-throughput sequencing can efficiently identify such variants among the patients and enable the definite diagnosis.

[Analysis of a child with Verheij syndrome due to variant of PUF60 gene].

OBJECTIVE: To explore the clinical phenotype and genetic variant in a child with Verheij syndrome (VRJS). METHODS: A child who had presented at the Soochow University Affiliated Children's Hospital and Wujiang District Children's Hospital in July 2022 for "elevated scapula since early childhood" was selected as the study subject. Peripheral blood samples of the child and his parents were collected and subjected to whole exome sequencing. Candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: The child had manifested elevated scapulae, torticollis, neck asymmetry, facial dysmorphism, dispersed café-au-lait spots, limited mobility of upper limbs and shoulder joints, and intellectual disability. Sequencing revealed that he has harbored a de novo heterozygous c.405dupT (p.Ile136Tyrfs*4) variant of the PUF60 gene. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), this variant was classified as pathogenic (PVS1+PS2_moderate+PM2_supporting). Combined his clinical features and result of genetic testing, the child was diagnosed with VRJS due to variant of the PUF60 gene. CONCLUSION: The clinical manifestations of VRJS include facial dysmorphism, intellectual disability, elevated scapulae, vertebral fusion, other skeletal malformations, without significant abnormalities of the heart, kidney, and eyes, which need to be distinguished from Klippel-Feil syndrome. Above finding has expended the mutation spectrum of the PUF60 gene and provided a reference for delineation of the genotype-phenotype correlation of the VRJS.

Clinical, Radiologic, and Histopathologic Features that Distinguish a Pigmented Plexiform Neurofibroma from a Congenital Melanocytic Nevus.

A 13-year-old Hispanic boy with no significant medical etymology presented with a chief complaint of widespread brown macules and patches. He had a large and evenly pigmented brown patch, with a centrally located 2.2 cm × 1.2 cm soft and darkly pigmented plaque, which became more apparent with tension applied to the surrounding skin (Figure 1). The patient's mother stated that the plaque was present since birth and had increased in size over time. The clinical differential diagnoses included a congenital melanocytic nevus (CMN), a large café au lait macule (CALM), and a Becker's nevus with a congenital smooth muscle hamartoma.

Case Report: Severe McCune-Albright syndrome presenting with neonatal Cushing syndrome: navigating through clinical obstacles.

Background: Café-au-lait skin macules, Cushing syndrome (CS), hyperthyroidism, and liver and cardiac dysfunction are presenting features of neonatal McCune-Albright syndrome (MAS), CS being the rarest endocrine feature. Although spontaneous resolution of hypercortisolism has been reported, outcome is usually unfavorable. While a unified approach to diagnosis, treatment, and follow-up is lacking, herein successful treatment and long-term follow-up of a rare case is presented. Clinical case: An 11-day-old girl born small for gestational age presented with deterioration of well-being and weight loss. Large hyperpigmented macules on the trunk, hypertension, hyponatremia, hyperglycemia, and elevated liver enzymes were noted. ACTH-independent CS due to MAS was diagnosed. Although metyrapone (300 mg/m2/day) was started on the 25th day, complete remission could not be achieved despite increasing the dose up to 1,850 mg/m2/day. At 9 months, right total and left three-quarters adrenalectomy was performed. Cortisol decreased substantially, ACTH remained suppressed, rapid tapering of hydrocortisone to physiological dose was not tolerated, and supraphysiological doses were required for 2 months. GNAS analysis from the adrenal tissue showed a pathogenic heterozygous mutation. During 34 months of follow-up, in addition to CS due to MAS, fibrous dysplasia, hypophosphatemic rickets, and peripheral precocious puberty were detected. She is still regularly screened for other endocrinopathies. Conclusion: Neonatal CS due to MAS is extremely rare. Although there is no specific guideline for diagnosis, treatment, or follow-up, addressing side effects and identifying treatment outcomes will improve quality of life and survival.

[MULTIPLE CAFÉ-AU-LAIT MACULES AND INTERTRIGINOUS FRECKLING: BEYOND THE RASOPATHIES].

INTRODUCTION: Piebaldism is the dominantly inherited skin disorder clinically characterized by congenital stable and well circumscribed patches of leukoderma (depigmented skin) of ventral distribution, involving central forehead, frontal chest and abdomen and central portion of limbs, and by localized poliosis (white hair). Inherited or de novo mutations in proto-oncogene KIT, encoding the transmembrane tyrosine kinase receptor c-kit, underly the majority of piebaldism cases. Piebaldism is a disorder characterized by incomplete penetrance and variable expressivity.

Occipital bone defect caused by neurofibromatosis type I: A case report.

RATIONALE: The synergistic effect between nonmalignant lesions can also cause a serious impact on patient survival. This disease involves different organ systems and presents with a variety of clinical manifestations, such as schwannoma, depigmentation, low-grade glioma, and skeletal abnormalities. We report a case of type I neurofibromatosis with an occipital bone defect. PATIENT CONCERNS: We report a case of a 50-year-old man with type I neurofibromatosis with occipital bone defect. DIAGNOSIS: The patient was accepted by the local hospital due to sudden right upper limb weakness accompanied by jitter without recognizable cause or inducement. A computerized tomography scan at a local hospital suggested subcutaneous neurofibromatosis with a left occipital cranial defect with thinning bone. On admission physical examination, diffuse multiple masses could be seen throughout the body and head of different sizes and composed of soft and tough textures. The largest one was located in the posterior occipital bone, approximately 8*8 cm in size, with a child tumor and tough texture. Multiple café-au-lait spots could be found on the chest and back, and multiple freckles can be seen in the armpit. The patient underwent surgery. Postoperative pathology showed a spindle cell tumor, which was determined to be neurofibromatosis type I according to immunopathology and clinical data. INTERVENTIONS: The patient was admitted for surgical treatment. During the operation, the scalp mass was completely abducted and the tumor tissue at the skull defect was sharply separated. Postoperative pathology showed that the peripheral margin and the bottom margin were cleaned. OUTCOMES: Computerized tomography and magnetic resonance imaging showed that the tumor was completely. There were not any surgical complications. The patient recovered well, was cured and was dismissed from the hospital. LESSONS: The synergistic effect between nonmalignant lesions can also cause a serious impact on patient survival to encourage early medical intervention. The clinical presentation of neurofibromatosis type I am usually nonmalignant, and in this case, involvement of the skull with bone defect is very rare. Therefore, it is necessary to accumulate relevant cases, reveal the pathogenesis of the disease, predict the development and outcome, and provide more evidence for early therapeutic intervention of similar patients in the future.

Characteristics of Café-au-lait Macules and their Association with the Neurofibromatosis type I Genotype in a Cohort of Greek Children.

Cafe-au-lait macules are the most distinctive clinical finding in neurofibromatosis type I. The aim of this prospective study of Greek children diagnosed with neurofibromatosis type I was to describe the dermatological phenotype and to analyse the characteristics of cafe-au-lait macules and their association with genotype. Pigment intensity and melatonin content of cafe-au-lait macules were measured with a narrowband spectrophotometer. A total of 63 children aged 6 months to 16 years old were studied. Mean melanin content varied, both among patients, and within each patient (p < 0.001). Females had a higher number of cafe-au-lait macules than did males (p = 0.025), and the melanin content of cafe-au-lait macules was lower in females than males (p < 0.001). Patients with protein-truncating variants in the neurofibromatosis type I gene had higher melanin content of cafe-au-lait macules than other types of genetic variants t (55) = 2.196, p = 0.032. Plexiform neurofibromas were also detected in the majority of patients with protein- truncating variants, while juvenile xanthogranulomas were detected equally in patients with protein-truncating and non-protein-truncating variants. In conclusion, cafe-au-lait macules with high melatonin content are associated with patients carrying non-protein-truncating variants. Therefore, measurement of cafe-au-lait macule pigment intensity might provide useful information for initial assessment of patients with neurofibromatosis type I and the severity of their future phenotype.

Genetic evaluation of 50 Turkish patients with neurofibromatosis type 1: 2 years experience of a single center.

BACKGROUND/AIM: Neurofibromatosis type 1 is an autosomal dominant neurocutaneous disorder. Clinical diagnosis is difficult in early childhood, and it is possible to miss a critical interval for tumour screening. In this study, we aimed to characterize the mutational spectrum of Turkish patients and discuss the benefits of molecular testing. MATERIAL AND METHODS: Fifty individuals from 35 unrelated families were included. Main referral reasons for genetic testing were as follows: to confirm a clinical diagnosis, to use in differential diagnosis and to evaluate first-degree family member of a known patient. Two-step process consisting of initial next generation sequencing of the NF1 gene and consequent multiplex ligation-dependent probe amplification were performed. RESULTS: We identified a total of 30 variants in 28 individuals. Variant detection rate was 56% in the entire study group and 71.4% within the index patients. Four novel variants were found. Truncating variants constituted 60% of the entire mutation spectrum. A deletion or duplication was not detected. The most common feature was cafe au lait macules in 70% of the patients, followed by focal areas of signal intensity on brain imaging (26%), cutaneous neurofibromas (24%) and axillary freckling (24%). CONCLUSIONS: Early sequencing in all suspected patients followed by deletion/duplication analysis in patients meeting clinical criteria and a case-to-case based consideration for RNA studies seems to be the effective algorithm for NF-1 diagnosis.

Aneurysms involving the coronary arteries in a neonate with neurofibromatosis 1.

Aneurysmal coronary artery disease (ACAD) has been reported rarely in patients with neurofibromatosis type 1 (NF1), mostly in adults. We report on a female newborn affected by NF1 with ACAD disclosed during investigation for an abnormal prenatal ultrasound along with a review of the previously reported cases. The proposita had multiple café-au-lait spots and had no cardiac symptoms. Echocardiography, and cardiac computed tomography angiography confirmed aneurysms on the left coronary artery, left anterior descending coronary artery, and of the sinus of Valsalva. Molecular analysis detected the pathogenic variant NM_001042492.3(NF1):c.3943C>T (p.Gln1315*). Literature findings on ACAD in NF1 indicated that this mostly occurs in males, showing predilection for the development of aneurysms at the left anterior descending coronary artery, and manifesting predominantly as acute myocardial infarction, inclusively in teenagers, though it may be also asymptomatic as in our case. This report documents the first case of ACAD in a patient with NF1 diagnosed at birth, emphasizing that its early diagnosis is essential to prevent potential life-threatening events attributable directly to coronary lesions.