Majewski osteodysplastic primordial dwarfism type II (MOPD II): expanding the vascular phenotype

Pericentrin deficiency in smooth muscle cells augments atherosclerosis through HSF1-driven cholesterol biosynthesis and PERK activation

Microcephalic osteodysplastic primordial dwarfism type II (MOPDII) is caused by biallelic loss-of-function variants in pericentrin (PCNT), and premature coronary artery disease (CAD) is a complication of the syndrome. Histopathology of coronary arteries from patients with MOPDII who died of CAD in their 20s showed extensive atherosclerosis. Hyperlipidemic mice with smooth muscle cell-specific (SMC-specific) Pcnt deficiency (PcntSMC-/-) exhibited significantly greater atherosclerotic plaque burden compared with similarly treated littermate controls despite similar serum lipid levels. Loss of PCNT in SMCs induced activation of heat shock factor 1 (HSF1) and consequently upregulated the expression and activity of HMG-CoA reductase (HMGCR), the rate-limiting enzyme in cholesterol biosynthesis. The increased cholesterol biosynthesis in PcntSMC-/- SMCs augmented PERK signaling and phenotypic modulation compared with control SMCs. Treatment with the HMGCR inhibitor, pravastatin, blocked the augmented SMC modulation and reduced plaque burden in hyperlipidemic PcntSMC-/- mice to that of control mice. These data support the notion that Pcnt deficiency activates cellular stress to increase SMC modulation and plaque burden, and targeting this pathway with statins in patients with MOPDII has the potential to reduce CAD in these individuals. The molecular mechanism uncovered further emphasizes SMC cytosolic stress and HSF1 activation as a pathway driving atherosclerotic plaque formation independently of cholesterol levels.

Intracranial Aneurysms and Genetics: An Extensive Overview of Genomic Variations, Underlying Molecular Dynamics, Inflammatory Indicators, and Forward-Looking Insights

This review initiates by outlining the clinical relevance of IA, underlining the pressing need to comprehend its foundational elements. We delve into the assorted risk factors tied to IA, spotlighting both environmental and genetic influences. Additionally, we illuminate distinct genetic syndromes linked to a pronounced prevalence of intracranial aneurysms, underscoring the pivotal nature of genetics in this ailment's susceptibility. A detailed scrutiny of genome-wide association studies allows us to identify key genomic changes and locations associated with IA risk. We further detail the molecular and physiopathological dynamics instrumental in IA's evolution and escalation, with a focus on inflammation's role in affecting the vascular landscape. Wrapping up, we offer a glimpse into upcoming research directions and the promising horizons of personalized therapeutic strategies in IA intervention, emphasizing the central role of genetic insights. This thorough review solidifies genetics' cardinal role in IA, positioning it as a cornerstone resource for professionals in the realms of neurology and genomics.

Case Report: short stature, kidney anomalies, and cerebral aneurysms in a novel homozygous mutation in the PCNT gene associated with microcephalic osteodysplastic primordial dwarfism type II

We report the case of a boy (aged 3 years and 7 months) with severe growth failure (length: -9.53 SDS; weight: -9.36 SDS), microcephaly, intellectual disability, distinctive craniofacial features, multiple skeletal anomalies, micropenis, cryptorchidism, generalized hypotonia, and tendon retraction. Abdominal US showed bilateral increased echogenicity of the kidneys, with poor corticomedullary differentiation, and a slightly enlarged liver with diffuse irregular echotexture. Initial MRI of the brain, performed at presentation, showed areas of gliosis with encephalomalacia and diffused hypo/delayed myelination, and a thinned appearance of the middle and anterior cerebral arteries. Genetic analysis evidenced a novel homozygous pathogenic variant of the pericentrin (PCNT) gene. PCNT is a structural protein expressed in the centrosome that plays a role in anchoring of protein complexes, regulation of the mitotic cycle, and cell proliferation. Loss-of-function variants of this gene are responsible for microcephalic osteodysplastic primordial dwarfism type II (MOPDII), a rare inherited autosomal recessive disorder. The boy died at 8 years of age as a result of an intracranial hemorrhage due to a cerebral aneurism associated with the Moyamoya malformation. In confirmation of previously published results, intracranial anomalies and kidney findings were evidenced very early in life. For this reason, we suggest including MRI of the brain with angiography as soon as possible after diagnosis in follow-up of MODPII, in order to identify and prevent complications related to vascular anomalies and multiorgan failure.

The Genetic Landscape of Ischemic Stroke in Children - Current Knowledge and Future Perspectives

Stroke in childhood has multiple etiologies, which are mostly distinct from those in adults. Genetic discoveries over the last decade pointed to monogenic disorders as a rare but significant cause of ischemic stroke in children and young adults, including small vessel and arterial ischemic stroke. These discoveries contributed to the understanding that stroke in children may be a sign of an underlying genetic disease. The identification of these diseases requires a detailed medical and family history collection, a careful clinical evaluation for the detection of systemic symptoms and signs, and neuroimaging assessment. Establishing an accurate etiological diagnosis and understanding the genetic risk factors for stroke are essential steps to decipher the underlying mechanisms, optimize the design of tailored prevention strategies, and facilitate the identification of novel therapeutic targets in some cases. Despite the increasing recognition of monogenic causes of stroke, genetic disorders remain understudied and therefore under-recognized in children with stroke. Increased awareness among healthcare providers is essential to facilitate accurate diagnosis in a timely manner. In this review, we provide a summary of the main single-gene disorders which may present as ischemic stroke in childhood and describe their clinical manifestations. We provide a set of practical suggestions for the diagnostic work up of these uncommon causes of stroke, based upon the stroke subtype and imaging characteristics that may suggest a monogenic diagnosis of ischemic stroke in children. Current hurdles in the genetic analyses of children with ischemic stroke as well as future prospectives are discussed.

Clinical and Genetic Analysis of a Patient With Coexisting 17a-Hydroxylase/17,20-Lyase Deficiency and Moyamoya Disease

17a-Hydroxylase/17,20-lyase deficiency (17OHD) is caused by pathogenic mutations in CYP17A1. Female patients present with hypertension, hypokalemia, and sexual infantilism while males present with sex development disorder. Moyamoya disease (MMD) is a chronic cerebrovascular disease that frequently results in intracranial ischemia or hemorrhage. The present study describes a case of 17OHD and MMD in a 27-year-old phenotypically female (46, XY) patient and discusses the clinical features and characteristics of her genetic defect. Clinical, hormonal, radiological, and genetic analyses were performed and blood samples were collected for whole-exome sequencing (WES). The results of the WES revealed a homozygous intronic mutation (c.297+2T>C) in CYP17A1, which led to combined 17a-hydroxylase/17,20-lyase deficiency, as well as novel variants in PCNT and CNOT3 that might lead to MMD. To our knowledge, this study is the first to describe 17OHD accompanied by MMD. While several cases have previously described patients with 17OHD with histories of cerebral hemorrhage or cerebral ischemia, a correlation in genetic levels between 17OHD and MMD was not found. The risk of cerebrovascular accidents should be considered in patients with 17OHD and hypertension. Cerebrovascular examination in patients with 17OHD may be beneficial for the prevention of life-threatening intracranial vascular disease.

Microcephalic Osteodysplastic Primordial Dwarfism Type II With Associated Glucose-6-Phosphate Dehydrogenase Deficiency in a Saudi Girl

Microcephalic primordial dwarfism is a group of disorders that result in growth restriction and multiple morbidities. The condition is subdivided into three categories, with microcephalic osteodysplastic primordial dwarfism type II (MOPDII) being the most prevalent. Globally, only a few cases have been reported, with only available information about these disorders described in the literature. In this case report, we present the clinical findings seen in an infant with MOPDII in Saudi Arabia with associated glucose-6-phosphate dehydrogenase deficiency hemolytic anemia.

Central nervous system vasculopathy and Seckel syndrome: case illustration and systematic review

PURPOSE

To systematically review reported cases of Seckel syndrome (SS) and point out cases associated with central nervous system (CNS) vasculopathy and provide a summary of their clinical presentation, management, and outcomes including our illustrative case.

METHODS

We conducted a search on the MEDLINE, PubMed, Google Scholar, and Cochrane databases using the keywords "Seckel + syndrome." We identified 127 related articles reporting 252 cases of SS apart from our case. Moreover, we searched for SS cases with CNS vasculopathies from the same databases. We identified 7 related articles reporting 7 cases of CNS vasculopathies in SS patients.

RESULTS

The overall rate of CNS vasculopathy in SS patients is 3.16% (n = 8/253), where moyamoya disease (MMD) accounted for 1.97%. The mean age is 13.5 years (6-19 years), with equal gender distribution (M:F, 1:1). The most common presenting symptoms were headache and seizure followed by weakness or coma. Aneurysms were mostly located in the basilar artery, middle cerebral artery, and internal carotid artery, respectively. Regardless of the management approach, 50% of the cases sustained mild-moderate neurological deficit, 37.5% have died, and 12.5% sustained no deficit.

CONCLUSION

A high index of suspicion should be maintained in (SS) patients, and MMD should be part of the differential diagnosis. Prevalence of CNS vasculopathy in SS is 3.16% with a much higher prevalence of MMD compared to the general population. Screening for cerebral vasculopathy in SS is justifiable especially in centers that have good resources. Further data are still needed to identify the most appropriate management plan in these cases.

Western Moyamoya Phenotype: A Scoping Review

Moyamoya, a rare angiographic finding, is characterized by chronic and progressive stenosis at the terminal end of the internal carotid artery, followed by collateralization of the cerebral vasculature at the base of the skull. Coined by Suzuki and Takaku in 1969, the term "moyamoya" means a "puff of smoke" in Japanese, a reference to the angiographic appearance of moyamoya collateralization. Moyamoya is most commonly found in East Asian countries, where much governmental and civilian effort has been expended to characterize this unique disease process. However, despite its rarity, the occurrence of moyamoya in Western countries is associated with significant divergence regarding incidence, gender, sex, age at diagnosis, clinical presentation, and outcomes. Here, we attempted to review the Western literature on moyamoya presentation using the PubMed database to characterize the Western phenotype of moyamoya. We were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR). We reviewed papers generated from a search with keywords "moyamoya case report," those reported from a Western institution, and those reported on a relevant association. Our scoping review demonstrated various clinical associations with moyamoya. Moreover, we summarized the demographic profile and clinical symptomatology, as well as reported disease associations to better elucidate the Western phenotype of moyamoya.

Genetics of Intracranial Aneurysms

Rupture of an intracranial aneurysm leads to aneurysmal subarachnoid hemorrhage, a severe type of stroke which is, in part, driven by genetic variation. In the past 10 years, genetic studies of IA have boosted the number of known genetic risk factors and improved our understanding of the disease. In this review, we provide an overview of the current status of the field and highlight the latest findings of family based, sequencing, and genome-wide association studies. We further describe opportunities of genetic analyses for understanding, prevention, and treatment of the disease.

A novel homozygous mutation of the PCNT gene in a Chinese patient with microcephalic osteodysplastic primordial dwarfism type II

Background

Microcephalic osteodysplastic primordial dwarfism type II (MOPD II) is a rare autosomal recessive disorder characterized by severe pre‐ and postnatal growth restrictions, microcephaly, skeletal dysplasia, severe teeth deformities, and typical facial features. Previous studies have shown that MOPD II is associated with mutations in the pericentrin (PCNT) gene.

Methods

We evaluated the clinical features of a 10‐year and 7‐month‐old Chinese girl with MOPD II. Subsequently, next‐generation sequencing and flow cytometry were performed to investigate genetic characteristics and the expression of PCNT protein respectively.

Results

The patient presented with short stature, microcephaly, typical craniofacial features, teeth deformity, thrombocytosis, and a delayed bone age (approximately 7 years). No abnormality in growth hormone or insulin‐like growth factor 1 was detected. Notably, the patient was found to carry a novel homozygous PCNT mutation (c.6157G>T, p.Glu2053Ter), which was inherited from her healthy heterozygous parents. Meanwhile, significant deficiency of PCNT expression was identified in the patient.

Conclusion

Our study identified a novel PCNT mutation associated with MOPD II, expanded the mutation spectrum of the PCNT gene and improved our understanding of the molecular basis of MOPD II.

Microcephalic osteodysplastic primordial dwarfism type II is associated with global vascular disease

BACKGROUND

Microcephalic osteodysplastic primordial dwarfism type II (MOPDII) is the most common form of primordial dwarfism, caused by bialleic mutations in the pericentrin gene (PCNT). Aside from its classic features, there are multiple associated medical complications, including a well-documented risk of neurovascular disease. Over the past several years, it has become apparent that additional vascular issues, as well as systemic hypertension and kidney disease may also be related to MOPDII. However, the frequency and extent of the vasculopathy was unclear. To help address this question, a vascular substudy was initiated within our Primordial Dwarfism Registry.

RESULTS

Medical records from 47 individuals, living and deceased, ranging in age from 3 to 41 years of age were interrogated for this purpose. Of the total group, 64% were diagnosed with moyamoya, intracranial aneurysms, or both. In general, the age at diagnosis for moyamoya was younger than aneurysms, but the risk for neurovascular disease was throughout the shortened lifespan. In addition to neurovascular disease, renal, coronary and external carotid artery involvement are documented. 43% of the total group was diagnosed with hypertension, and 17% had myocardial infarctions. A total of 32% of the entire cohort had some form of chronic kidney disease, with 4% of the total group necessitating a kidney transplant. In addition, 38% had diabetes/insulin resistance. Ages of diagnoses, treatment modalities employed, and location of vasculopathies were notated as available and applicable, as well as frequencies of other comorbidities.

CONCLUSIONS

It is now clear that vascular disease in MOPDII is global and screening of the cardiac and renal vessels is warranted along with close monitoring of blood pressure. We recommend a blood pressure of 110/70 mmHg as a starting point for an upper limit, especially if the individual has a history of neurovascular disease, chronic kidney disease and/or diabetes. Additionally, providers need to be at high alert for the possibility of myocardial infarctions in young adults with MOPDII, so that appropriate treatment can be initiated promptly in an acute situation.

Siblings With Familial Dwarfism Presenting With Acute Myocardial Infarction at Adolescence

We encountered siblings with familial Majewski osteodysplastic primordial dwarfism type II (MOPD II) with acute myocardial infarction in adolescence and in their early 20s. We successfully performed percutaneous and surgical coronary interventions. From these cases, we were able to better understand coronary artery disease of MOPD II and provide better management. (Level of Difficulty: Intermediate.)

Microcephalic osteodysplastic primordial dwarfism type II and pachygyria: Morphometric analysis in a 2-year-old girl

Microcephalic osteodysplastic primordial dwarfism (MOPD) type II is a rare disorder characterized by skeletal dysplasia, severe proportionate short stature, insulin resistance and cerebrovascular abnormalities including cerebral aneurysms and moyamoya disease. MOPD type II is caused by mutations in the pericentrin (PCNT) gene, which encodes a protein involved in centrosomes function. We report a 2 year old girl affected by MOPD type II caused by two compound heterozygous loss-of-function variants in PCNT gene, of which one is a novel variant (c.5304delT; p.Gly1769AlafsTer34). The patient presented atypical brain magnetic resonance imaging (MRI) findings consistent with pachygyria. This was confirmed by morphometric analysis of cortical thickness (CT) and gyrification index by comparing MRI data of the patient with a group of eight age-matched healthy controls. The statistical analysis revealed a significant and diffuse increase of CT with an anterior-predominant pattern and diffuse reduced gyrification (p < .05). These findings provide new evidences to the emergent concept that malformations of cortical development are complex disorders and that new genetic findings contribute to the fading of classification borders.

NOVEL XRCC4 MUTATIONS IN AN INFANT WITH MICROCEPHALIC PRIMORDIAL DWARFISM, DILATED CARDIOMYOPATHY, SUBCLINICAL HYPOTHYROIDISM, AND EARLY DEATH: EXPANDING THE PHENOTYPE OF XRCC4 MUTATIONS

Objective

Microcephalic primordial dwarfism (MPD) is a group of clinically and genetically heterogeneous disorders which result in severe prenatal and postnatal growth failure. X-ray repair cross-complementing protein 4 (XRCC4) is a causative gene for an autosomal recessive form of MPD. The objective of this report is to describe novel XRCC4 mutations in a female infant with MPD, dilated cardiomyopathy, and subclinical hypothyroidism.

Methods

Genetic testing was performed using a comprehensive next generation sequencing panel for MPD, followed by targeted XRCC4 gene sequencing.

Results

We report the case of a 970-gram, 35-cm, female infant (weight z score -5.05, length z score -4.71) born at 36 weeks and 3 days gestation. Physical examination revealed triangular facies, micrognathism, clinodactyly, and second and third toe syndactyly. Initial echocardiogram at birth was normal. Follow-up echocardiogram at 60 days of life revealed dilated cardiomyopathy with moderate left ventricular systolic dysfunction (ejection fraction was 40 to 45%), and anticongestive therapy was initiated. Thyroid testing revealed subclinical hypothyroidism with elevated thyroid-stimulating hormone of 13.0 μIU/mL (reference range is 0.3 to 5.0 μIU/mL) and normal free thyroxine by dialysis of 1.6 ng/dL (reference range is 0.8 to 2.0 ng/dL). Levothyroxine was initiated. Postnatal growth remained poor (weight z score at 3 months -4.93, length z score at 3 months -6.48), including progressive microcephaly (head circumference z score at 3 months -10.94). Genetic testing revealed novel compound heterozygous XRCC4 variants in trans: c.628A>T and c.638+3A>G. The child ultimately had cardiopulmonary arrest and died at 6 months of life.

Conclusion

Molecular diagnosis in MPD is key to defining the natural history, management, and prognosis for patients with these rare disorders.

Intracranial aneurysms in microcephalic primordial dwarfism: a systematic review

BACKGROUND

Microcephalic primordial dwarfism (MPD) is a heterogeneous group of rare disorders. Recent studies have reported a significant percentage of patients with MPD suffering from a spectrum of cerebrovascular abnormalities, including intracranial aneurysms (IAs) and moyamoya syndrome. The neurological literature has not as yet specifically assessed IAs in this population. This systematic review aimed to assess the clinical behavior, characteristics, treatment modalities and outcomes of IAs in patients with MPD.

METHODS

We performed a systematic search in PubMed, Ovid MEDLINE and Ovid EMBASE for cases of MPD with IAs. We included three illustrative cases from our institution.

RESULTS

Twenty-four patients with 71 aneurysms were included in this study. Twelve patients (50%) presented with subarachnoid hemorrhage. The majority of patients were aged ≤18 years (70.8%), with a mean age of 16.2 years at presentation. Median aneurysm size was 3 (IQR 1.8-6) mm, and the most frequent locations were the internal carotid (37.3%) and middle cerebral arteries (23.8%). Concomitant moyamoya disease was reported in nine (37.5%) patients. Median age of aneurysm detection in screened patients was significantly lower than in non-screened patients (P=0.02). Microsurgical clipping (55.3%) and endovascular coiling (26.3%) were the most used modalities. Twenty-two cases were managed conservatively. Overall, mortality occurred in 45.8% of cases.

CONCLUSIONS

Screening for cerebrovascular disease seems reasonable and effective to detect aneurysms at an earlier age in this population. Efforts in the literature to emphasize early and regular screening for these patients can positively impact outcomes in this population, however more evidence is needed.

Intracranial vascular pathology in two further patients with Floating-Harbor syndrome: Proposals for cerebrovascular disease risk management

Floating-Harbor syndrome (FHS) is a rare, heritable disorder caused by variants in the SRCAP gene. Most individuals with FHS have characteristic facial features, short stature, and speech and language impairment. Although FHS has been likely under-diagnosed due to a combination of lack of recognition of the clinical phenotype and limited access to genomic testing, it is a rare condition with around 100 individuals reported in the medical literature. Case series have been biased towards younger individuals (vast majority <20 years of age) meaning that it has been challenging to provide accurate medical advice for affected individuals in adulthood. We report two young adults with FHS who presented with intracranial haemorrhage likely secondary to cerebrovascular aneurysms, with devastating consequences, making a total of four FHS patients reported with significant cerebrovascular abnormalities. Three of four patients had hypertension, at least one in conjunction with normal renal structure. We consider possible relationships between hypertension, renal pathology and aneurysms in the context of FHS, and consider mechanisms through which disruption of the SRCAP protein may lead to vascular pathology. We recommend that clinicians should have a low threshold to investigate symptoms suggestive of cerebrovascular disease in FHS. We advise that patients with FHS should have annual blood pressure monitoring from adolescence, renal ultrasound at diagnosis repeated in adulthood, and timely investigation of any neurological symptoms. For patients with FHS, particularly with hypertension, we advise that clinicians should consider at least one MRA (Magnetic Resonance Imaging with Angiography) to check for cerebral aneurysms.

Ocular characteristics in a variant microcephalic primordial dwarfism type II

BACKGROUND

Microcephalic osteodysplastic primordial dwarfism, type II (MOPD II) is a rare disease that is assumed to be caused by a pericentrin (PCNT) gene mutation. Clinical manifestations have been reported in pediatrics and neurology; however, only a few ocular findings have been documented.

CASE PRESENTATION

We present three unrelated cases of MOPD II with similar facial features and short stature. Unlike the cases described in the literature, all subjects had normal birth weight and height but their growth was retarded thereafter. In addition to delayed milestones, they have a broad forehead, maxillary protrusion, long peaked nose, high nasal bridge, low-set large ears, extreme reromicrogenia, and normal-sized teeth. These three patients had similar ocular manifestations with the short axial length associated with high hyperopia more than + 9 diopters (D) and macular scarring. The oldest subject was a 20 year-old male without neurological symptoms. One female subject had developed alopecia during the previous 2 years. The other female subject had moyamoya disease, but a genetic study revealed a normal PCNT gene.

CONCLUSION

This is the first report of MOPD II focusing on ocular findings, suggesting that macular dystrophy and high hyperopia are the common ocular characteristics of MOPD II. Prompt referral to an ophthalmologist is essential. Although refractive amblyopia can be treated with optical correction, visual prognosis may be poor due to maculopathy.

The pleiotropy associated with de novo variants in CHD4, CNOT3, and SETD5 extends to moyamoya angiopathy

PURPOSE

Moyamoya angiopathy (MMA) is a cerebrovascular disease characterized by occlusion of large arteries, which leads to strokes starting in childhood. Twelve altered genes predispose to MMA but the majority of cases of European descent do not have an identified genetic trigger.

METHODS

Exome sequencing from 39 trios were analyzed.

RESULTS

We identified four de novo variants in three genes not previously associated with MMA: CHD4, CNOT3, and SETD5. Identification of additional rare variants in these genes in 158 unrelated MMA probands provided further support that rare pathogenic variants in CHD4 and CNOT3 predispose to MMA. Previous studies identified de novo variants in these genes in children with developmental disorders (DD), intellectual disability, and congenital heart disease.

CONCLUSION

These genes encode proteins involved in chromatin remodeling, and taken together with previously reported genes leading to MMA-like cerebrovascular occlusive disease (YY1AP1, SMARCAL1), implicate disrupted chromatin remodeling as a molecular pathway predisposing to early onset, large artery occlusive cerebrovascular disease. Furthermore, these data expand the spectrum of phenotypic pleiotropy due to alterations of CHD4, CNOT3, and SETD5 beyond DD to later onset disease in the cerebrovascular arteries and emphasize the need to assess clinical complications into adulthood for genes associated with DD.

Majewski dwarfism type II: an atypical neuroradiological presentation with a novel variant in the PCNT gene

Microcephalic osteodysplastic primordial dwarfism syndrome II (MOPDII) is microcephalic primordial dwarfism and is a very rare form of disproportionate short stature. This disorder shares common features with other forms of microcephalic primordial dwarfism, including severe prenatal and postnatal growth retardation with marked microcephaly. However, it includes characteristic skeletal dysplasia, abnormal dentition and increased risk for cerebrovascular diseases. Recent reports added more features, including café-au-lait lesions, cutis marmorata, astigmatism, Moyamoya disease, insulin resistance, obesity, abnormal skin pigmentation and acanthosis nigricans around the neck. Clearly, the more MOPDII reports that are produced, the more information will be added to the spectrum of MOPDII features that can improve our understanding of this disorder. In this paper, we reported a new case of MOPDII with more severe clinical features, earlier onset of common features, in addition to a homozygous novel variant in the PCNT gene.

Intracranial Aneurysms: Pathology, Genetics, and Molecular Mechanisms

Intracranial aneurysms (IA) are local dilatations in cerebral arteries that predominantly affect the circle of Willis. Occurring in approximately 2-5% of adults, these weakened areas are susceptible to rupture, leading to subarachnoid hemorrhage (SAH), a type of hemorrhagic stroke. Due to its early age of onset and poor prognosis, SAH accounts for > 25% of years lost for all stroke victims under the age of 65. In this review, we describe the cerebrovascular pathology associated with intracranial aneurysms. To understand IA genetics, we summarize syndromes with elevated incidence, genome-wide association studies (GWAS), whole exome studies on IA-affected families, and recent research that established definitive roles for Thsd1 (Thrombospondin Type 1 Domain Containing Protein 1) and Sox17 (SRY-box 17) in IA using genetically engineered mouse models. Lastly, we discuss the underlying molecular mechanisms of IA, including defects in vascular endothelial and smooth muscle cells caused by dysfunction in mechanotransduction, Thsd1/FAK (Focal Adhesion Kinase) signaling, and the Transforming Growth Factor β (TGF-β) pathway. As illustrated by THSD1 research, cell adhesion may play a significant role in IA.

Bioengineering an Artificial Human Blood⁻Brain Barrier in Rodents

Our group has recently created a novel in-vivo human brain organoid vascularized with human iPSC-derived endothelial cells. In this review article, we discuss the challenges of creating a perfused human brain organoid model in an immunosuppressed rodent host and discuss potential applications for neurosurgical disease modeling.

Identification of a novel PCNT founder pathogenic variant in the Israeli Druze population

Majewski Osteodysplastic Primordial Dwarfism type II (MOPDII) is a form of dwarfism associated with severe microcephaly, characteristic skeletal findings, distinct dysmorphic features and increased risk for cerebral infarctions. The condition is caused by bi-allelic loss-of-function variants in the gene PCNT. Here we describe the identification of a novel founder pathogenic variant c.3465-1G > A observed in carriers from multiple Druze villages in Northern Israel. RNA studies show that the variant results in activation of a cryptic splice site causing a coding frameshift. The study was triggered by the diagnosis of a single child with MOPDII and emphasizes the advantages of applying next generation sequencing technologies in community genetics and the importance of establishing population-specific sequencing databases.

Microduplication of 15q13.3 and Microdeletion of 18q21.32 in a Patient with Moyamoya Syndrome

Moyamoya angiopathy (MA) is a cerebrovascular disease determining a progressive stenosis of the terminal part of the internal carotid arteries (ICAs) and their proximal branches and the compensatory development of abnormal “moyamoya” vessels. MA occurs as an isolated cerebral angiopathy (so-called moyamoya disease) or in association with various conditions (moyamoya syndromes) including several heritable conditions such as Down syndrome, neurofibromatosis type 1 and other genomic defects. Although the mechanism that links MA to these genetic syndromes is still unclear, it is believed that the involved genes may contribute to the disease susceptibility. Herein, we describe the case of a 43 years old woman with bilateral MA and peculiar facial characteristics, having a 484-kb microduplication of the chromosomal region 15q13.3 and a previously unreported 786 kb microdeletion in 18q21.32. This patient may have a newly-recognized genetic syndrome associated with MA. Although the relationship between these genetic variants and MA is unclear, our report would contribute to widening the genetic scenario of MA, in which not only genic mutation, but also genome unbalances are possible candidate susceptibility factors.

PCNT point mutations and familial intracranial aneurysms

OBJECTIVE

To identify novel genes involved in the etiology of intracranial aneurysms (IAs) or subarachnoid hemorrhages (SAHs) using whole-exome sequencing.

METHODS

We performed whole-exome sequencing in 13 individuals from 3 families with an autosomal dominant IA/SAH inheritance pattern to look for candidate genes for disease. In addition, we sequenced PCNT exon 38 in a further 161 idiopathic patients with IA/SAH to find additional carriers of potential pathogenic variants.

RESULTS

We identified 2 different variants in exon 38 from the PCNT gene shared between affected members from 2 different families with either IA or SAH (p.R2728C and p.V2811L). One hundred sixty-four samples with either SAH or IA were Sanger sequenced for the PCNT exon 38. Five additional missense mutations were identified. We also found a second p.V2811L carrier in a family with a history of neurovascular diseases.

CONCLUSION

The PCNT gene encodes a protein that is involved in the process of microtubule nucleation and organization in interphase and mitosis. Biallelic loss-of-function mutations in PCNT cause a form of primordial dwarfism (microcephalic osteodysplastic primordial dwarfism type II), and ≈50% of these patients will develop neurovascular abnormalities, including IAs and SAHs. In addition, a complete Pcnt knockout mouse model (Pcnt ^-/-) published previously showed general vascular abnormalities, including intracranial hemorrhage. The variants in our families lie in the highly conserved PCNT protein-protein interaction domain, making PCNT a highly plausible candidate gene in cerebrovascular disease.

Unruptured intracranial aneurysms: An updated review of current concepts for risk factors, detection and management

The management of patients with unruptured intracranial aneurysms (UIAs) is a complex clinical challenge and constitutes an immense field of research. While a preponderant proportion of these aneurysms never rupture, the consequences of such an event are severe and represent an important healthcare problem. To date, however, the natural history of UIAs is not completely understood and there is no accurate means to discriminate the UIAs that will rupture from those that will not. Yet, a good understanding of the recent evidence and future perspectives is needed when advising a patient with IA to tailor any information to the given patient's level of risk and psychoaffective status. Thus, this review addresses the current concepts of epidemiology, risk factors, detection and management of UIAs.

Microcephalic Osteodysplastic Primordial Dwarfism, Type II: a Clinical Review

PURPOSE OF THE REVIEW

This review will provide an overview of the microcephalic primordial dwarfism (MPD) class of disorders and provide the reader comprehensive clinical review with suggested care guidelines for patients with microcephalic osteodysplastic primordial dwarfism, type II (MOPDII).

RECENT FINDINGS

Over the last 15 years, significant strides have been made in the diagnosis, natural history, and management of MOPDII. MOPDII is the most common and well described form of MPD. The classic features of the MPD group are severe pre- and postnatal growth retardation, with marked microcephaly. In addition to these features, individuals with MOPDII have characteristic facies, skeletal dysplasia, abnormal dentition, and an increased risk for cerebrovascular disease and insulin resistance. Biallelic loss-of-function mutations in the pericentrin gene cause MOPDII, which is inherited in an autosomal recessive manner.

Surgical outcomes of Majewski osteodysplastic primordial dwarfism Type II with intracranial vascular anomalies

OBJECTIVE Majewski osteodysplastic primordial dwarfism Type II (MOPD II) is a rare genetic disorder. Features of it include extremely small stature, severe microcephaly, and normal or near-normal intelligence. Previous studies have found that more than 50% of patients with MOPD II have intracranial vascular anomalies, but few successful surgical revascularization or aneurysm-clipping cases have been reported because of the diminutive arteries and narrow surgical corridors in these patients. Here, the authors report on a large series of patients with MOPD II who underwent surgery for an intracranial vascular anomaly. METHODS In conjunction with an approved prospective registry of patients with MOPD II, a prospectively collected institutional surgical database of children with MOPD II and intracranial vascular anomalies who underwent surgery was analyzed retrospectively to establish long-term outcomes. RESULTS Ten patients with MOPD II underwent surgery between 2005 and 2012; 5 patients had moyamoya disease (MMD), 2 had intracranial aneurysms, and 3 had both MMD and aneurysms. Patients presented with transient ischemic attack (TIA) (n = 2), ischemic stroke (n = 2), intraparenchymal hemorrhage from MMD (n = 1), and aneurysmal subarachnoid hemorrhage (n = 1), and 4 were diagnosed on screening. The mean age of the 8 patients with MMD, all of whom underwent extracranial-intracranial revascularization (14 indirect, 1 direct) was 9 years (range 1-17 years). The mean age of the 5 patients with aneurysms was 15.5 years (range 9-18 years). Two patients experienced postoperative complications (1 transient weakness after clipping, 1 femoral thrombosis that required surgical repair). During a mean follow-up of 5.9 years (range 3-10 years), 3 patients died (1 of subarachnoid hemorrhage, 1 of myocardial infarct, and 1 of respiratory failure), and 1 patient had continued TIAs. All of the surviving patients recovered to their neurological baseline. CONCLUSIONS Patients with MMD presented at a younger age than those in whom aneurysms were more prevalent. Microneurosurgery with either intracranial bypass or aneurysm clipping is extremely challenging but feasible at expert centers in patients with MOPD II, and good long-term outcomes are possible.

Loss of function of the Drosophila Ninein-related centrosomal protein Bsg25D causes mitotic defects and impairs embryonic development

The centrosome-associated proteins Ninein (Nin) and Ninein-like protein (Nlp) play significant roles in microtubule stability, nucleation and anchoring at the centrosome in mammalian cells. Here, we investigate Blastoderm specific gene 25D (Bsg25D), which encodes the only Drosophila protein that is closely related to Nin and Nlp. In early embryos, we find that Bsg25D mRNA and Bsg25D protein are closely associated with centrosomes and astral microtubules. We show that sequences within the coding region and 3′UTR of Bsg25D mRNAs are important for proper localization of this transcript in oogenesis and embryogenesis. Ectopic expression of eGFP-Bsg25D from an unlocalized mRNA disrupts microtubule polarity in mid-oogenesis and compromises the distribution of the axis polarity determinant Gurken. Using total internal reflection fluorescence microscopy, we show that an N-terminal fragment of Bsg25D can bind microtubules in vitro and can move along them, predominantly toward minus-ends. While flies homozygous for a Bsg25D null mutation are viable and fertile, 70% of embryos lacking maternal and zygotic Bsg25D do not hatch and exhibit chromosome segregation defects, as well as detachment of centrosomes from mitotic spindles. We conclude that Bsg25D is a centrosomal protein that, while dispensable for viability, nevertheless helps ensure the integrity of mitotic divisions in Drosophila.

Summary: In humans, mutations in Ninein or Ninein-like protein result in microcephaly and other severe diseases. We show that while flies lacking the Ninein orthologue can survive, many die as embryos with defects in mitosis.

National Analysis of 2454 Pediatric Moyamoya Admissions and the Effect of Hospital Volume on Outcomes

BACKGROUND AND PURPOSE

Comprehensive multicenter data on treatment of pediatric moyamoya in the United States is lacking. We sought to identify national trends in the diagnosis and treatment of this disease.

METHODS

A total of 2454 moyamoya admissions from 1997 to 2012 were identified from the Kids Inpatient Database. Demographics, inpatient costs, interventions, and discharge status were analyzed. Admissions with and without surgical revascularization were reviewed separately. The effect of hospital moyamoya volume on outcomes was analyzed by multivariate regression analysis.

RESULTS

Care of moyamoya patients has been concentrating at high-volume centers during the past 12 years. Among moyamoya admission without surgical revascularization, high-volume hospitals show no difference in length of stay, cost, or complications compared with low-volume centers. However, low-volume hospitals have more nonroutine discharges (odds ratio, 2.32; P=0.0005) and inpatient deaths (odds ratio, 12.7; P=0.02) when no revascularization was performed. In contrast, among admissions with surgical revascularization, high-volume centers had decreased length of stay (4.7 versus 6.2 days; P=0.004), reduced cost ($88 000 versus $138 000; P<0.0001), and no increase in complications (P=0.29) compared with low-volume centers. Admissions with revascularization to low-volume hospitals also had increased likelihood of nonroutine discharge (odds ratio, 8.23; P=0.02) compared with high-volume centers.

CONCLUSIONS

This is the largest study of US pediatric moyamoya admissions to date. These data demonstrate that volume correlates with outcome, indicating high-volume centers provide significantly improved care and reduced mortality in pediatric moyamoya patients, with the most marked benefit observed in admissions for surgical revascularization.

A new horizon of moyamoya disease and associated health risks explored through RNF213

The cerebrovascular disorder moyamoya disease (MMD) was first described in 1957 in Japan, and is typically considered to be an Asian-specific disease. However, it is globally recognized as one of the major causes of childhood stroke. Although several monogenic diseases are known to be complicated by Moyamoya angiopathy, the ring finger protein 213 gene (RNF213) was identified as a susceptibility gene for MMD. RNF213 is unusual, because (1) it induces MMD with no other recognizable phenotypes, (2) the RNF213 p.R4810K variant is an Asian founder mutation common to Japanese, Korean and Chinese with carrier rates of 0.5–2 % of the general population but a low penetrance, and (3) it encodes a relatively largest proteins with a dual AAA+ ATPase and E3 Ligase activities. In this review, we focus on the genetics and genetic epidemiology of RNF213, the pathology of RNF213 R4810K, and the molecular functions of RNF213, and also address the public health contributions to current unresolved issues of MMD. We also emphasize the importance of a more updated definition for MMD, of qualified cohort studies based on genetic epidemiology and an awareness of the ethical issues associated with genetic testing of carriers.

Identification of two novel critical mutations in PCNT gene resulting in microcephalic osteodysplastic primordial dwarfism type II associated with multiple intracranial aneurysms

Microcephalic osteodysplastic primordial dwarfism type II (MOPD II) is a highly detrimental human autosomal inherited recessive disorder. The hallmark characteristics of this disease are intrauterine and postnatal growth restrictions, with some patients also having cerebrovascular problems such as cerebral aneurysms. The genomic basis behind most clinical features of MOPD II remains largely unclear. The aim of this work was to identify the genetic defects in a Chinese family with MOPD II associated with multiple intracranial aneurysms. The patient had typical MOPD II syndrome, with subarachnoid hemorrhage and multiple intracranial aneurysms. We identified three novel mutations in the PCNT gene, including one single base alteration (9842A>C in exon 45) and two deletions (Del-C in exon 30 and Del-16 in exon 41). The deletions were co-segregated with the affected individual in the family and were not present in the control population. Computer modeling demonstrated that the deletions may cause drastic changes on the secondary and tertiary structures, affecting the hydrophilicity and hydrophobicity of the mutant proteins. In conclusion, we identified two novel mutations in the PCNT gene associated with MOPD II and intracranial aneurysms, and the mutations were expected to alter the stability and functioning of the protein by computer modeling.

Primordial dwarfism: overview of clinical and genetic aspects

Primordial dwarfism is a group of genetic disorders which include Seckel Syndrome, Silver-Russell Syndrome, Microcephalic Osteodysplastic Primordial Dwarfism types I/III, II and Meier-Gorlin Syndrome. This genetic disorder group is characterized by intra-uterine growth retardation and post-natal growth abnormalities which occur as a result of disorganized molecular and genomic changes in embryonic stage and, thus, it represents a unique area to study growth and developmental abnormalities. Lot of research has been carried out on different aspects; however, a consolidated review that discusses an overall spectrum of this disorder is not accessible. Recent research in this area points toward important molecular and cellular mechanisms in human body that regulate the complexity of growth process. Studies have emerged that have clearly associated with a number of abnormal chromosomal, genetic and epigenetic alterations that can predispose an embryo to develop PD-associated developmental defects. Finding and associating such fundamental changes to its subtypes will help in re-examination of alleged functions at both cellular and developmental levels and thus reveal the intrinsic mechanism that leads to a balanced growth. Although such findings have unraveled a subtle understanding of growth process, we further require active research in terms of identification of reliable biomarkers for different subtypes as an immediate requirement for clinical utilization. It is hoped that further study will advance the understanding of basic mechanisms regulating growth relevant to human health. Therefore, this review has been written with an aim to present an overview of chromosomal, molecular and epigenetic modifications reported to be associated with different subtypes of this heterogenous disorder. Further, latest findings with respect to clinical and molecular genetics research have been summarized to aid the medical fraternity in their clinical utility, for diagnosing disorders where there are overlapping physical attributes and simultaneously inform about the latest developments in PD biology.

Guidelines for the Management of Patients With Unruptured Intracranial Aneurysms: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association

PURPOSE

The aim of this updated statement is to provide comprehensive and evidence-based recommendations for management of patients with unruptured intracranial aneurysms.

METHODS

Writing group members used systematic literature reviews from January 1977 up to June 2014. They also reviewed contemporary published evidence-based guidelines, personal files, and published expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulated recommendations using standard American Heart Association criteria. The guideline underwent extensive peer review, including review by the Stroke Council Leadership and Stroke Scientific Statement Oversight Committees, before consideration and approval by the American Heart Association Science Advisory and Coordinating Committee.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with unruptured intracranial aneurysms. The guidelines address presentation, natural history, epidemiology, risk factors, screening, diagnosis, imaging and outcomes from surgical and endovascular treatment.

Flow diversion for complex intracranial aneurysms in young children

Pediatric intracranial aneurysms are exceedingly rare and account for less than 5% of all intracranial aneurysms. Open surgery to treat such aneurysms has been shown to be more durable than endovascular techniques, and durability of treatment is particularly important in the pediatric population. Over the past 2 decades, however, a marked shift in aneurysm treatment from open surgery toward endovascular procedures has occurred for adults. The authors describe their early experience in treating 3 unruptured pediatric brain aneurysms using the Pipeline embolization device (PED). The first patient, a girl with Majewski osteodysplastic primordial dwarfism Type II who was harboring multiple intracranial aneurysms, underwent two flow diversion procedures for a vertebrobasilar aneurysm and a supraclinoid internal carotid artery aneurysm. The second patient underwent PED placement on a previously coiled but enlarging posterior communicating artery aneurysm. All procedures were uneventful, with no postsurgical complications, and led to complete angiographic obliteration of the aneurysms. To the authors' knowledge, this is the first series of flow diversion procedures in children reported in the medical literature. While flow diversion is a new and relatively untested technology in children, outcomes in adults have been promising. For challenging lesions in the pediatric population, flow diversion may have a valuable role as a well-tolerated, safe treatment with durable results. Many issues remain to be addressed, such as the durability of flow diverters over a very long follow-up and vessel response to growth in the presence of an endoluminal device.

Moyamoya disease and syndromes: from genetics to clinical management

Moyamoya angiopathy is characterized by a progressive stenosis of the terminal portion of the internal carotid arteries and the development of a network of abnormal collateral vessels. This chronic cerebral angiopathy is observed in children and adults. It mainly leads to brain ischemic events in children, and to ischemic and hemorrhagic events in adults. This is a rare condition, with a marked prevalence gradient between Asian countries and Western countries. Two main nosological entities are identified. On the one hand, moyamoya disease corresponds to isolated moyamoya angiopathy, defined as being “idiopathic” according to the Guidelines of the Research Committee on the Pathology and Treatment of Spontaneous Occlusion of the Circle of Willis. This entity is probably multifactorial and polygenic in most patients. On the other hand, moyamoya syndrome is a moyamoya angiopathy associated with an underlying condition and forms a very heterogeneous group with various clinical presentations, various modes of inheritance, and a variable penetrance of the cerebrovascular phenotype. Diagnostic and evaluation techniques rely on magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) conventional angiography, and cerebral hemodynamics measurements. Revascularization surgery can be indicated, with several techniques. Characteristics of genetic moyamoya syndromes are presented, with a focus on recently reported mutations in BRCC3/MTCP1 and GUCY1A3 genes. Identification of the genes involved in moyamoya disease and several monogenic moyamoya syndromes unraveled different pathways involved in the development of this angiopathy. Studying genes and pathways involved in monogenic moyamoya syndromes may help to give insights into pathophysiological models and discover potential candidates for medical treatment strategies.

Primordial dwarfism: an update

PURPOSE OF REVIEW

To review the recent advances in the clinical and molecular characterization of primordial dwarfism, an extreme growth deficiency disorder that has its onset during embryonic development and persists throughout life.

RECENT FINDINGS

The last decade has witnessed an unprecedented acceleration in the discovery of genes mutated in primordial dwarfism, from one gene to more than a dozen genes. These genetic discoveries have confirmed the notion that primordial dwarfism is caused by defects in basic cellular processes, most notably centriolar biology and DNA damage response. Fortunately, the increasing number of reported clinical primordial dwarfism subtypes has been accompanied by more accurate molecular classification.

SUMMARY

Qualitative defects of centrioles with resulting abnormal mitosis dynamics, reduced proliferation, and increased apoptosis represent the predominant molecular pathogenic mechanism in primordial dwarfism. Impaired DNA damage response is another important mechanism, which we now know is not mutually exclusive to abnormal centrioles. Molecular characterization of primordial dwarfism is helping families by enabling more reproductive choices and may pave the way for the future development of therapeutics.

Majewski osteodysplastic primordial dwarfism type II: clinical findings and dental management of a child patient

Majewski osteodysplastic primordial dwarfism type II (MOPD II) is an unusual autosomal recessive inherited form of primordial dwarfism, which is characterized by a small head diameter at birth, but which also progresses to severe microcephaly, progressive bony dysplasia, and characteristic facies and personality. This report presents a case of a five-year-old girl with MOPD II syndrome. The patient was referred to our clinic with the complaint of severe tooth pain at the left mandibular primary molar teeth. Clinical examination revealed that most of the primary teeth had been decayed and all primary teeth were hypoplastic. Patient’s history revealed delayed development in the primary dentition and radiographic examination showed rootless primary molar teeth and short-rooted incisors. The treatment was not possible due to the lack of root of the left mandibular primary molars; so the teeth were extracted. Thorough and timely dental evaluation is crucial for the prevention of dental problems and the maintenance of oral health in patients with MOPD II syndrome is of utmost importance.

A unique set of centrosome proteins requires pericentrin for spindle-pole localization and spindle orientation

Majewski osteodysplastic primordial dwarfism type II (MOPDII) is caused by mutations in the centrosome gene pericentrin (PCNT) that lead to severe pre- and postnatal growth retardation. As in MOPDII patients, disruption of pericentrin (Pcnt) in mice caused a number of abnormalities including microcephaly, aberrant hemodynamics analyzed by in utero echocardiography, and cardiovascular anomalies; the latter being associated with mortality, as in the human condition. To identify the mechanisms underlying these defects, we tested for changes in cell and molecular function. All Pcnt(-/-) mouse tissues and cells examined showed spindle misorientation. This mouse phenotype was associated with misdirected ventricular septal growth in the heart, decreased proliferative symmetric divisions in brain neural progenitors, and increased misoriented divisions in fibroblasts; the same phenotype was seen in fibroblasts from three MOPDII individuals. Misoriented spindles were associated with disrupted astral microtubules and near complete loss of a unique set of centrosome proteins from spindle poles (ninein, Cep215, centriolin). All these proteins appear to be crucial for microtubule anchoring and all interacted with Pcnt, suggesting that Pcnt serves as a molecular scaffold for this functionally linked set of spindle pole proteins. Importantly, Pcnt disruption had no detectable effect on localization of proteins involved in the cortical polarity pathway (NuMA, p150(glued), aPKC). Not only do these data reveal a spindle-pole-localized complex for spindle orientation, but they identify key spindle symmetry proteins involved in the pathogenesis of MOPDII.

Hip pathology in Majewski osteodysplastic primordial dwarfism type II

INTRODUCTION

Majewski osteodysplastic primordial dwarfism type II (MOPDII) is characterized by severe prenatal and postnatal growth failure with microcephaly, characteristic skeletal dysplasia, an increased risk for cerebrovascular disease, and insulin resistance. MOPDII is caused by mutations in the pericentrin (PCNT) gene and is inherited in an autosomal-recessive manner. This study aimed to determine the incidence of hip pathology in patients with molecularly confirmed MOPDII and to describe the functional outcomes of surgical treatment.

METHODS

Thirty-three enrolled patients had a clinical diagnosis of MOPDII. Biallelic PCNT mutations or absent pericentrin protein was confirmed in 25 of these patients. Twelve patients (7 female) had appropriate clinical and radiographic records at this institution and were included in this study. The data collected included age at presentation, age at surgery, sex, body weight and height, weight-bearing status at diagnosis, and the clinical examination.

RESULTS

Four patients (31%) had coxa vara: 3 unilateral and 1 bilateral. Three unilateral patients had in situ pinning at a mean age 4 years. The patient with bilateral coxa vara had valgus osteotomy at the age of 5 years. Two children had bilateral hip dysplasia and subluxation with no surgery. One patient had bilateral developmental hip dislocations. The patient was treated by open reduction-spica cast and 2 years after surgery, coxa valga was noted. Another patient was diagnosed at an age of 12 years with bilateral avascular necrosis of the hips. Four patients did not have hip pathology.

CONCLUSIONS

Hip pathology is common among children with MOPDII; coxa vara is the most frequent diagnosis. Routine clinical and radiographic hip evaluation is important. The capital femoral epiphysis appears to slip down along the shaft, giving the appearance of a proximal femoral epiphysiolysis. A hip diagnosed with slipped capital femoral epiphysis in early life may progress to severe coxa vara.

LEVEL OF EVIDENCE

Level IV.

Screening for cerebrovascular disease in microcephalic osteodysplastic primordial dwarfism type II (MOPD II): an evidence-based proposal

Microcephalic osteodysplastic primordial dwarfism type II (OMIM 210720) is a rare autosomal recessive condition frequently associated with early-onset cerebrovascular disease. Presymptomatic detection and intervention could prevent the adverse consequences associated with this. We reviewed published cases of microcephalic osteodysplastic primordial dwarfism type II to ascertain prevalence and characteristics of cerebrovascular disease and use these data to propose an evidence-based approach to cerebrovascular screening. Of 147 cases identified, 47 had cerebrovascular disease (32%), including occlusive arteriopathy (including moyamoya) and cerebral aneurysmal disease. Occlusive disease occurred in younger individuals, and progression can be both rapid and clinically silent. A reasonable screening approach would be magnetic resonance imaging and angiography of the cervical and intracranial circulation at diagnosis, repeated at yearly intervals until 10 years, and every 2 years thereafter, unless clinical concerns occur earlier. At present it would appear that this needs to be life-long. Families and professionals should be alerted to the potential significance of neurologic symptoms and measures should be taken to maintain good vascular health in affected individuals.