Congenital mydriasis and prune belly syndrome in a child with an ACTA2 mutation

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.

Megacystis Associated With an Underlying ACTA2 Variant and Diagnosis of Multisystemic Smooth Muscle Dysfunction Syndrome: A Case Report

Fetal megacystis, or an enlarged fetal bladder, is most often attributed to embryological defects, occurring early in gestation. Recent investigations have demonstrated that the underlying etiology of megacystis may be more myriad than originally thought. We present the third reported patient with megacystis due to an ACTA2 Arg179 substitution variant causing Multisystemic Smooth Muscle Dysfunction Syndrome. We also provide a description of pediatric evaluation and follow up. The growing number of cases in which this ACTA2 variant has been identified in fetal megacystis suggests that molecular sequencing is an appropriate consideration, particularly prenatally, when other features of Multisystemic Smooth Muscle Dysfunction Syndrome cannot be detected.

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.

Prune-belly syndrome in Africa: An analysis and systematic review of cases, etiology, treatment, and outcomes

Background:

Prune-belly syndrome is a rare congenital disorder characterized by a spectrum of three anomalies: bilateral undescended testes, dilated urinary tract, and anterior abdominal muscle deficiency.

Objectives:

In developing countries, inadequate access to health care may affect treatment and outcomes of prune-belly syndrome. This study’s goal was to review the anatomical features, etiology, genetics, management, and outcomes of cases in Africa.

Methods:

PubMed was searched to identify case reports and case studies describing prune-belly syndrome in Africa. Data collected from each study included the number of cases, age at diagnosis, sex, description of the abdominal muscles, testes, and urinary tract, as well as associated anomalies, management, and long-term outcomes.

Results:

A total of 16 publications that reported 58 cases in African countries were included. The prevalence of female patients (15.5%) was higher than in developed countries (3%). The abdominal muscles were deficient in all cases, and bilateral cryptorchidism was present in nearly all males (96%). Distension of the bladder was common, with normal anatomy reported in only one case. Bilateral hydroureters and hydronephrosis also were present in the majority of cases. Only six cases (10.3%) had no associated anomalies, such as musculoskeletal or cardiovascular. Karyotyping was performed in only three cases (5.2%) because of limited hospital facilities. Six parents (10.3%) declined treatment for their children, 12 cases (20.7%) were managed conservatively, and 25 (43.1%) received surgical intervention. Patients’ mortality rate was higher than in developed countries.

Conclusion:

Diagnosis and treatment of prune-belly syndrome remains a challenge in Africa, in which multiple factors, such as access to health care and cultural beliefs, affect mortality rates and outcomes. Patient education and support groups may improve compliance with treatment.

Level of evidence:

Not applicable for this multicenter audit.

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

BACKGROUND

Congenital mydriasis and retinal arteriolar tortuosity are associated with the life-threatening multisystemic smooth muscle dysfunction syndrome (MSMDS) due to mutations in the gene, ACTA2, which encodes alpha-smooth muscle actin (α-SMA). Previous reports attributed MSMDS-related congenital mydriasis to the absence of iris sphincter muscle. Similarly, it has been hypothesized that abnormal proliferation of the vascular smooth muscle cells causes the marked tortuosity of retinal arterioles in MSMDS. In this report, high-resolution ocular imaging reveals unexpected findings that reject previous hypotheses.

CASE PRESENTATION

The proband is a 37-year-old female with a history of neonatal patent ductus arteriosus (PDA) ligation, left-sided choreiform movements at the age of 11 and a transient aphasia with right-sided weakness at the age of 30. Her older sister also had PDA ligation and congenital mydriasis but no neurological deficit up to age 41. Magnetic resonance angiogram demonstrated cerebrovascular lesions resembling but distinct from Moyamoya disease, characterised by internal carotid artery dilatation, terminal segment stenosis and absent basal collaterals. Their mother had poorly reactive pupils with asymptomatic cerebral arteriopathy resembling her daughters. All three had prominent retinal arteriolar tortuosity. The daughters were heterozygous and the mother was a somatic mosaic for a novel c.351C > G (p.Asn117Lys) transversion in ACTA2. Iris optical coherence tomography (OCT) showed a hyporeflective band anterior to the pigment epithelium indicating the presence of dysfunctional sphincter muscle. Adaptive optics retinal imaging showed no thickening of the arteriolar vessel wall whilst OCT angiography showed extreme corkscrew course of arterioles suggesting vessel elongation.

CONCLUSIONS

In addition to the known association between Met46, Arg179 and Arg258 substitutions and ACTA2-related arteriopathy, this case illustrates the possibility that Asn117 also plays an important role in α-SMA function within the cerebrovascular smooth muscle cell. MSMDS-related congenital mydriasis is due to reduced iris sphincter contractility rather than its absence. Retinal arteriolar tortuosity might be due to longitudinal proliferation of arteriolar smooth muscle cells. The described cerebrovascular and ocular signs are consistent with predicted effects of the novel Asn117Lys substitution in ACTA2.

Prune belly syndrome in surviving males can be caused by Hemizygous missense mutations in the X-linked Filamin A gene

Background

Prune belly syndrome (PBS) is a rare, multi-system congenital myopathy primarily affecting males that is poorly described genetically. Phenotypically, its morbidity spans from mild to lethal, however, all isolated PBS cases manifest three cardinal pathological features: 1) wrinkled flaccid ventral abdominal wall with skeletal muscle deficiency, 2) urinary tract dilation with poorly contractile smooth muscle, and 3) intra-abdominal undescended testes. Despite evidence for a genetic basis, previously reported PBS autosomal candidate genes only account for one consanguineous family and single cases.

Methods

We performed whole exome sequencing (WES) of two maternal adult half-brothers with syndromic PBS (PBS + Otopalatodigital spectrum disorder [OPDSD]) and two unrelated sporadic individuals with isolated PBS and further functionally validated the identified mutations.

Results

We identified three unreported hemizygous missense point mutations in the X-chromosome gene Filamin A (FLNA) (c.4952 C > T (p.A1448V), c.6727C > T (p.C2160R), c.5966 G > A (p.G2236E)) in two related cases and two unrelated sporadic individuals. Two of the three PBS mutations map to the highly regulatory, stretch-sensing Ig19–21 region of FLNA and enhance binding to intracellular tails of the transmembrane receptor β-integrin 1 (ITGβ1).

Conclusions

FLNA is a regulatory actin-crosslinking protein that functions in smooth muscle cells as a mechanosensing molecular scaffold, transmitting force signals from the actin-myosin motor units and cytoskeleton via binding partners to the extracellular matrix. This is the first evidence for an X-linked cause of PBS in multiple unrelated individuals and expands the phenotypic spectrum associated with FLNA in males surviving even into adulthood.

Multisystem smooth muscle dysfunction syndrome in a Chinese girl: A case report and review of the literature

BACKGROUND

Multisystemic smooth muscle dysfunction syndrome (MSMDS) is a rare genetic disease worldwide. The main mutation is the actin alpha 2 (ACTA2) gene p.R179H. In this paper, we report a Chinese MSMDS patient and systematically review the previous literature.

CASE SUMMARY

Here, we report a 9.6-month-old Chinese girl who was diagnosed with MSMDS based on her history and symptoms, such as recurrent cough, wheezing, and complications with congenital fixed dilated pupils. Chest high-resolution computed tomography revealed inhomogeneous lung transparency, obvious exudative lesions, and some lung fissures that were markedly thickened. Cranial magnetic resonance imaging excluded bleeding and infarction but showed abnormal signals in the centrum ovale majus and bilateral periventricular regions. Echocardiography only showed patent foramen ovale, and no patent ductus arteriosus, pulmonary artery dilatation, or pulmonary hypertension was found. Bronchoscopy indicated moderate bronchial malacia. These examinations in conjunction with the typical eye abnormality suggested a diagnosis of MSMDS, and sequencing of exon 6 of the ACTA2 gene demonstrated the heterozygous mutation c.536G>A, p.R179H. However, her parents’ gene analyses were normal.

CONCLUSION

MSMDS is a rare genetic disease mainly caused by the mutation of the ACTA2 gene p.R179H. Early genetic diagnosis should be performed for children presenting with congenital fixed dilated pupils and patent ductus arteriosus. During the process of diagnosis and treatment, clinicians should be on high alert for cerebrovascular, cardiovascular, and pulmonary complications.

Phenotypic severity scoring system and categorisation for prune belly syndrome: application to a pilot cohort of 50 living patients

OBJECTIVE

To design a novel system of scoring prune belly syndrome (PBS) phenotypic severity at any presenting age and apply it to a large pilot cohort.

PATIENTS AND METHODS

From 2000 to 2017, patients with PBS were recruited to our prospective PBS study and medical records were cross-sectionally analysed, generating individualised RUBACE scores. We designed the pragmatic RUBACE-scoring system based on six sub-scores (R: renal, U: ureter, B: bladder/outlet, A: abdominal wall, C: cryptorchidism, E: extra-genitourinary, generating the acronym RUBACE), yielding a potential summed score of 0-31. The 'E' score was used to segregate syndromic PBS and PBS-plus variants. The cohort was scored per classic Woodard criteria and RUBACE scores compared to Woodard category.

RESULTS

In all, 48 males and two females had a mean (range) RUBACE score of 13.8 (8-25) at a mean age of 7.3 years. Segregated by phenotypic categories, there were 39 isolated PBS (76%), six syndromic PBS (12%) and five PBS-plus (10%) cases. The mean RUBACE scores for Woodard categories 1, 2, and 3 were 20.5 (eight patients), 13.8 (25), and 10.6 (17), respectively (P < 0.001).

CONCLUSIONS

RUBACE is a practical, organ/system level, phenotyping tool designed to grade PBS severity and categorise patients into isolated PBS, syndromic PBS, and PBS-plus groups. This standardised system will facilitate genotype-phenotype correlations and future prospective multicentre studies assessing medical and surgical treatment outcomes.

Copy number variations in a population with prune belly syndrome

Prune Belly Syndrome (PBS) is a congenital multisystem myopathy with mild to lethal severity. While of uncertain etiology, 95% male predominance and familial occurrence suggest a genetic basis. As copy number variations (CNVs) can cause unexplained genetic disorders, we tested for novel CNVs in a large PBS population. We genotyped 21 unrelated PBS patients by high-resolution array comparative genomic hybridization (aCGH) and phenotyped using a novel PBS severity scoring system. Available parents were screened for detected CNV via quantitative PCR (qPCR). We additionally screened for recurrence of identified novel candidate CNVs on 106 PBS probands by qPCR. We identified 10 CNVs in 8 of 21 PBS patients tested (38%). Testing confirmed inheritance from an unaffected biological parent in six patients; parental samples were unavailable in two probands. One candidate CNV includes duplication of the X-chromosome AGTR2 gene, known to function in urinary tract development. Subsequent screening of the larger PBS cohort did not identify any recurrent CNVs. Presence of CNV did not correlate with PBS severity scoring. CNVs were uncommon in this large PBS population, but analysis of identified variants may inform disease pathogenesis and reveal targets for therapeutic intervention for this rare, severe disorder.

Iris anomalies and the incidence of ACTA2 mutation

BACKGROUND

Central cysts of the iris pigment epithelium, or iris flocculi, are frequently reported in the literature in association with thoracic aortic aneurysm and dissection due to smooth muscle alpha-actin 2 (ACTA2) mutations. Children with ACTA2 mutations may also present with congenital mydriasis. We report our experience regarding the frequency of ACTA2 mutation in children with the above iris anomalies.

METHODS

This is a retrospective, consecutive case series of all children presenting for iris flocculi or congenital mydriasis at a single tertiary centre from October 2012 to December 2016.

RESULTS

13 children with iris flocculi and 3 with congenital mydriasis presented during the study period. 10 children with iris flocculi completed genetic testing, and none were positive for ACTA2 mutation. All children with congenital mydriasis presented with a multisystem smooth muscle dysfunction syndrome; two of these three children tested positive for missense R179 ACTA2 mutations.

CONCLUSIONS

In this series, ACTA2 mutation or copy number variation was not detected in children presenting for iris flocculi, whereas congenital mydriasis was associated with R179 mutation in both cases that tested positive for ACTA2 mutation. The case of congenital mydriasis without typical cardiac features of the R179 ACTA2 phenotype or intracranial vasculopathy was negative for ACTA2 mutation. While all children presenting with these iris anomalies should be offered a genetic evaluation, incidence data should inform genetic counselling, particularly in the absence of a family history of aneurysm or sudden death, or systemic signs of smooth muscle dysfunction.

Clinical history and management recommendations of the smooth muscle dysfunction syndrome due to ACTA2 arginine 179 alterations

PURPOSE

Smooth muscle dysfunction syndrome (SMDS) due to heterozygous ACTA2 arginine 179 alterations is characterized by patent ductus arteriosus, vasculopathy (aneurysm and occlusive lesions), pulmonary arterial hypertension, and other complications in smooth muscle-dependent organs. We sought to define the clinical history of SMDS to develop recommendations for evaluation and management.

METHODS

Medical records of 33 patients with SMDS (median age 12 years) were abstracted and analyzed.

RESULTS

All patients had congenital mydriasis and related pupillary abnormalities at birth and presented in infancy with a patent ductus arteriosus or aortopulmonary window. Patients had cerebrovascular disease characterized by small vessel disease (hyperintense periventricular white matter lesions; 95%), intracranial artery stenosis (77%), ischemic strokes (27%), and seizures (18%). Twelve (36%) patients had thoracic aortic aneurysm repair or dissection at median age of 14 years and aortic disease was fully penetrant by the age of 25 years. Three (9%) patients had axillary artery aneurysms complicated by thromboembolic episodes. Nine patients died between the ages of 0.5 and 32 years due to aortic, pulmonary, or stroke complications, or unknown causes.

CONCLUSION

Based on these data, recommendations are provided for the surveillance and management of SMDS to help prevent early-onset life-threatening complications.

Visceral myopathy: Clinical and molecular survey of a cohort of seven new patients and state of the art of overlapping phenotypes

Visceral motility dysfunction is a key feature of genetic disorders such as megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS, MIM moved from 249210 to 155310), chronic intestinal pseudo-obstruction (CIPO, MIM609629), and multisystemic smooth muscle dysfunction syndrome (MSMDS, MIM613834). The genetic bases of these conditions recently begun to be clarified with the identification of pathogenic variants in ACTG2, ACTA2, and MYH11 in individuals with visceral motility dysfunction. The MMIHS was associated with the heterozygous variant in ACTG2 and homozygous variant in MYH11, while the heterozygous variant in ACTA2 was observed in patients with MSMDS. In this study, we describe the clinical data as well as the molecular investigation of seven individuals with visceral myopathy phenotypes. Five patients presented with MMIHS, including two siblings from consanguineous parents, one had CIPO, and the other had MSMDS. In three individuals with MMIHS and in one with CIPO we identified heterozygous variant in ACTG2, one being a novel variant (c.584C>T-p.Thr195Ile). In the individual with MSMDS we identified a heterozygous variant in ACTA2. We performed the whole-exome sequencing in one sibling with MMIHS and her parents; however, the pathogenic variant responsible for her phenotype could not be identified. These results reinforce the clinical and genetic heterogeneity of the visceral myopathies. Although many cases of MMIHS are associated with ACTG2 variants, we suggest that other genes, besides MYH11, could cause the MMIHS with autosomal recessive pattern. © 2016 Wiley Periodicals, Inc.

Progressive Aortic Dilation Associated With ACTA2 Mutations Presenting in Infancy

Mutations in the gene ACTA2 are a recognized cause of aortic aneurysms with aortic dissection in adulthood. Recently, a specific mutation (Arg179His) in this gene has been associated with multisystem smooth muscle dysfunction presenting in childhood. We describe 3 patients with an R179H mutation, all of whom presented with an aneurysmal patent ductus arteriosus. Detailed information on the rate of aortic disease progression throughout childhood is provided. Death or need for ascending aortic replacement occurred in all patients. Genetic testing for ACTA2 mutations should be considered in all infants presenting with ductal aneurysms.