High-resolution iris and retinal imaging in multisystemic smooth muscle dysfunction syndrome due to a novel Asn117Lys substitution in ACTA2: a case report

Current clinical applications of anterior segment optical coherence tomography angiography: a review

Optical coherence tomography (OCT) is a revolutionary in vivo imaging technology that presents real-time information on ocular structures. Angiography based on OCT, known as optical coherence tomography angiography (OCTA), is a noninvasive and time-saving technique originally utilized for visualizing retinal vasculature. As devices and built-in systems have evolved, high-resolution images with depth-resolved analysis have assisted ophthalmologists in accurately localizing pathology and monitoring disease progression. With the aforementioned advantages, application of OCTA has extended from the posterior to anterior segment. This nascent adaptation showed good delineation of the vasculature in the cornea, conjunctiva, sclera, and iris. Thus, neovascularization of the avascular cornea and hyperemia or ischemic changes involving the conjunctiva, sclera, and iris has become prospective applications for AS-OCTA. Although traditional dye-based angiography is regarded as the gold standard in demonstrating vasculature in the anterior segment, AS-OCTA is expected to be a comparable but more patient-friendly alternative. In its initial stage, AS-OCTA has exhibited great potential in pathology diagnosis, therapeutic evaluation, presurgical planning, and prognosis assessments in anterior segment disorders. In this review of AS-OCTA, we aim to summarize scanning protocols, relevant parameters, and clinical applications as well as limitations and future directions. We are sanguine about its wide application in the future with the development of technology and refinement in built-in systems.

A familial missense ACTA2 variant p.Arg198Cys leading to Moyamoya-like arteriopathy with straight course of the intracranial arteries, aortic aneurysm and lethal aortic dissection

BACKGROUND

Cerebral vasculopathies frequently lead to severe medical conditions such as stroke or intracranial hemorrhage and have a broad range of possible etiologies that require different therapeutic regimens. However, vasculopathies sometimes present with characteristic angiographic findings, that - if recognized - can guide a more specific diagnostic work-up. Certain ACTA2 variants are associated with a distinctive cerebrovascular phenotype characterized by an anomalously straight course of intracranial arteries, dilatation of proximal ICA and stenosis of distal ICA, in the absence of a compensatory basal collateral network found in Moyamoya disease. Until recently, this ACTA2 cerebral arteriopathy has been reported only in ACTA2 variants impairing Arg179.

METHODS AND MATERIALS

We report a familial case of a missense ACTA2 variant p.Arg198Cys with angiographic features of an ACTA2 cerebral arteriopathy. We analyzed the neuroimaging features of all four variant carrying family members and discussed the cerebrovascular abnormalities we found on the background of the current literature on ACTA2 arteriopathies.

RESULTS

Neuroimaging of the variant carriers revealed angiographic abnormalities characteristic for ACTA2 cerebral arteriopathy such as stenoses of the terminal internal carotid artery, occlusion of the proximal middle cerebral artery and an anomalously straight course of the intracranial arteries. In our index patient catheter angiography showed a Moyamoya-like basal collateral network alongside with the above-mentioned features of an ACTA2 cerebral arteriopathy. The detected missense ACTA2 variant p.Arg198Cys was not known to be associated a cerebral arteriopathy, so far. One of the patients later died from aortic dissection - a common vascular complication of ACTA2 variants.

CONCLUSION

The familial case expands the phenotype of the detected ACTA2 variant p.Arg198Cys and hereby broadens the range of ACTA2 variants associated with a cerebral arteriopathy. Further, it emphasizes the importance of an interdisciplinary approach of vasculopathies.

Pearls and Pitfalls of Adaptive Optics Ophthalmoscopy in Inherited Retinal Diseases

Adaptive optics (AO) retinal imaging enables individual photoreceptors to be visualized in the clinical setting. AO imaging can be a powerful clinical tool for detecting photoreceptor degeneration at a cellular level that might be overlooked through conventional structural assessments, such as spectral-domain optical coherence tomography (SD-OCT). Therefore, AO imaging has gained significant interest in the study of photoreceptor degeneration, one of the most common causes of inherited blindness. Growing evidence supports that AO imaging may be useful for diagnosing early-stage retinal dystrophy before it becomes apparent on fundus examination or conventional retinal imaging. In addition, serial AO imaging may detect structural disease progression in early-stage disease over a shorter period compared to SD-OCT. Although AO imaging is gaining popularity as a structural endpoint in clinical trials, the results should be interpreted with caution due to several pitfalls, including the lack of standardized imaging and image analysis protocols, frequent ocular comorbidities that affect image quality, and significant interindividual variation of normal values. Herein, we summarize the current state-of-the-art AO imaging and review its potential applications, limitations, and pitfalls in patients with inherited retinal diseases.

Neonatal diagnosis of ACTA2-related disease: A case report and review of literature

Multisystemic smooth muscle dysfunction syndrome (MSMDS, OMIM # 613834) is a rare autosomal dominant condition caused by pathogenetic variants of ACTA2 gene that result in impaired muscle contraction. MSMDS is characterized by an increased susceptibility to aneurismal dilatations and dissections, patent ductus arteriosus, early onset coronary artery disease, congenital mydriasis, chronic interstitial lung disease, hypoperistalsis, hydrops of gall bladder, and hypotonic bladder. Here, we report an early diagnosis of a MSMDS related to ACTA2 p.Arg179His (R179H) mutation in a newborn and performed a review of the literature. An early diagnosis of MSMDS is extremely important, because of the severe involvement of cardiovascular system in the MSMDS. Multidisciplinary care and surveillance and timely management of symptoms are important to reduce the risk of complications.

Expanding the genetic and phenotypic spectrum of ACTA2-related vasculopathies in a Dutch cohort

PURPOSE

Heterozygous pathogenic/likely pathogenic (P/LP) variants in the ACTA2 gene confer a high risk for thoracic aortic aneurysms and aortic dissections. This retrospective multicenter study elucidates the clinical outcome of ACTA2-related vasculopathies.

METHODS

Index patients and relatives with a P/LP variant in ACTA2 were included. Data were collected through retrospective review of medical records using a standardized questionnaire.

RESULTS

A total of 49 individuals from 28 families participated in our study. In total, 20 different ACTA2 variants were detected. Aortic events occurred in 65% of the cases (78.6% index patients and 47.6% relatives). Male sex and hypertension emerged as significantly associated with aortic events. Of 20 individuals, 5 had an aortic diameter of <45 mm (1.77 inches) at the time of the type A dissection. Mean age at first aortic event was 49.0 ± 12.4 years. Severe surgical complications for type A and type B dissection occurred in 25% and 16.7% of the cases and in-hospital mortality rates were 9.5% and 0%, respectively.

CONCLUSION

P/LP ACTA2 variants are associated with an increased risk for an aortic event and age-related penetrance, which emphasizes the importance of early recognition of the disease. Caregivers should be aware of the risk for aortic dissections, even in individuals with aortic diameters within the normal range.

Expanding ACTA2 genotypes with corresponding phenotypes overlapping with smooth muscle dysfunction syndrome

Pathogenic variants in ACTA2, encoding smooth muscle α-actin, predispose to thoracic aortic aneurysms and dissections. ACTA2 variants altering arginine 179 predispose to a more severe, multisystemic disease termed smooth muscle dysfunction syndrome (SMDS; OMIM 613834). Vascular complications of SMDS include patent ductus arteriosus (PDA) or aortopulmonary window, early-onset thoracic aortic disease (TAD), moyamoya-like cerebrovascular disease, and primary pulmonary hypertension. Patients also have dysfunction of other smooth muscle-dependent systems, including congenital mydriasis, hypotonic bladder, and gut hypoperistalsis. Here, we describe five patients with novel heterozygous ACTA2 missense variants, p.Arg179Gly, p.Met46Arg, p.Thr204Ile, p.Arg39Cys, and p.Ile66Asn, who have clinical complications that align or overlap with SMDS. Patients with the ACTA2 p.Arg179Gly and p.Thr204Ile variants display classic features of SMDS. The patient with the ACTA2 p.Met46Arg variant exhibits exclusively vascular complications of SMDS, including early-onset TAD, PDA, and moyamoya-like cerebrovascular disease. The patient with the ACTA2 p.Ile66Asn variant has an unusual vascular complication, a large fusiform internal carotid artery aneurysm. The patient with the ACTA2 p.Arg39Cys variant has pulmonary, gastrointestinal, and genitourinary complications of SMDS but no vascular manifestations. Identifying pathogenic ACTA2 variants associated with features of SMDS is critical for aggressive surveillance and management of vascular and nonvascular complications and delineating the molecular pathogenesis of SMDS.

ACTA2 mutation is responsible for multisystemic smooth muscle dysfunction syndrome with seizures: A case report and review of literature

BACKGROUND

ACTA2 gene is a specific gene that encodes actin α2. Multisystem smooth muscle dysfunction syndrome (MSMDS) is a multisystem disease characterized by aortic and cerebrovascular lesions caused by ACTA2 gene mutations. There have been many reports of cardiac, pulmonary and cerebrovascular lesions caused by MSMDS; however, few studies have focused on seizures caused by MSMDS.

CASE SUMMARY

Our patient was a girl aged 7 years and 8 mo with recurrent cough, asthma and seizures for 7 years. She was diagnosed with severe pneumonia, congenital heart disease, cardiac insufficiency, and malnutrition in the local hospital. Cardiac ultrasonography revealed congenital heart disease, patent ductus arteriosus (with a diameter of 0.68 cm), left coronary arteriectasis, patent oval foramen (0.12 cm), tricuspid and pulmonary regurgitation, and pulmonary hypertension. Cerebral magnetic resonance imaging and magnetic resonance angiography indicated stiffness in the brain vessels, together with multiple aberrant signaling shadows in bilateral paraventricular regions. A heterozygous mutation (c.536G>A) was identified in the ACTA2 gene, resulting in generation of p.R179H. Finally, the girl was diagnosed with MSMDS combined with epilepsy. The patient had 4 episodes of seizures before treatment, and no onset of seizure was reported after oral administration of sodium valproate for 1 year.

CONCLUSION

MSMDS has a variety of clinical manifestations and unique cranial imaging features. Cerebrovascular injury and white matter injury may lead to seizures. Gene detection can confirm the diagnosis and prevent missed diagnosis or misdiagnosis.

Persistent anterior tunica vasculosa lentis in multisystemic smooth muscle dysfunction syndrome: A case report

RATIONALE

Multisystemic smooth muscle dysfunction syndrome (MSMDS) is a genetic disease that affects multiple organs. The report here concerns a patient with MSMDS, who is known so far as the youngest among all the reported patients. In addition to the typical manifestations, we observed previously unreported ocular abnormalities, including persistent anterior tunica vasculosa lentis (TVL) and early-onset retinal arteriolar tortuosity, by the fluorescein angiography (FA).

PATIENT CONCERNS

The patient was admitted to the neonatal intensive care unit immediately after birth for a diagnosis of urinary system dysplasia during fetal life. After a thorough examination, the patient was found with patent ductus arteriosus, pulmonary hypertension, cerebrovascular disease, hypotonic bladder, intestinal malrotation, and congenital mydriasis. The FA of the eyes undertaken in her 6-week demonstrated perfused vasculature in the persistent anterior TVL and prominent retinal arteriolar tortuosity. The whole exome sequencing revealed a de novo heterozygous ACTA2 gene missense mutation p.R179H.

DIAGNOSES

The patient was diagnosed with MSMDS.

INTERVENTIONS

Follow-up observation.

OUTCOMES

At the 3-month follow-up, no change of the ocular disease was observed.

LESSONS

The persistent anterior TVL in this case implies that ACTA2 p.R179H mutation affects not only the smooth muscle cells but also the pericytes, and further affects the TVL regression. The prominent retinal arteriolar tortuosity in this 6-week-old infant indicates that the retinal arteriolar tortuosity can present early in MSMDS.

Refractory cerebral infarction in a child with an ACTA2 mutation

INTRODUCTIONS

A specific mutation in the ACTA2 gene is known to cause multisystemic smooth muscle dysfunction syndrome, which is associated with cerebrovascular diseases and various organ disorders. Cerebral infarctions resulting from severe vasculopathy can be refractory; however, there are no previous reports describing the detailed clinical course of recurrent cerebral infarctions due to an ACTA2 mutation. Herein, we report a patient with an ACTA2 mutation who experienced multiple refractory cerebral infarctions in early childhood.

PATIENT DESCRIPTION

The patient was aged 1 year and 5 months at her first episode of cerebral infarction. Arteriopathy due to an ACTA2 mutation was diagnosed based on the characteristic cerebrovascular findings and abnormal physical findings, such as bilateral dilated pupils. Bilateral encephaloduroarteriosynangiosis and encephalogaleosynangiosis were performed after the first episode. Because the cerebral infarctions recurred postoperatively, administration of cilostazol followed by bosentan was started. However, despite these treatments she experienced seven cerebral infarctions by age 2 years and 6 months.

INTERPRETATION

Cerebral infarctions in patients with a specific ACTA2 mutation can occur even in early childhood, recur frequently, and cause severe motor and cognitive impairment. Physicians should be highly aware of this disease and be ready to provide the medical and surgical interventions necessary to minimize the disabling sequelae.