Copy number variation analysis in 98 individuals with PHACE syndrome

PHACES-like syndrome with TMEM260 compound heterozygous variants

PHACES syndrome is a multiple congenital disorder with unknown etiology that is characterized by Posterior fossa anomalies, Hemangioma, Arterial lesions, Cardiac abnormalities/coarctation of the aorta, Eye anomalies, and Sternal cleft. Compound heterozygous or homozygous TMEM260 variants cause structural heart defects and renal anomalies syndrome (SHDRA). We describe a 10-year-old male patient with a PHACES-like syndrome and TMEM260 compound heterozygous variants who demonstrated overlapping phenotypes between the two syndromes. He presented with truncus arteriosus, supraumbilical raphe, ophthalmological abnormality, vertebral abnormality, borderline intellectual disability, and hearing loss. He had normal serum creatinine. In proband exome sequencing, compound heterozygous TMEM260 variants (NM_017799.4 c.1617delG p.(Trp539Cysfs*9)/c.1858C > T p.(Gln620*)) were identified. Twelve patients have been reported with TMEM260-related SHDRA: 10 had truncus arteriosus and 6 had renal failure. One previously reported patient had facial port wine nevus and another patient had supraumbilical raphe, which are the cardinal signs for PHACES syndrome. TMEM260-related SHDRA could share overlapping clinical features with PHACES syndrome. This report expands the phenotypic spectrum of a TMEM260-related disorder.

Molecular Pathways and Possible Therapies for Head and Neck Vascular Anomalies

Vascular Anomalies are a heterogenous group of vascular lesions that can be divided, according to the International Society for the Study of Vascular Anomalies Classification, into two main groups : Vascular Tumors and Vascular Malformations. Vascular Malformations can be further subdivided into slow-flow and fast-flow malformations. This clinical and radiological classification allows for a better understanding of vascular anomalies and aims to offer a more precise final diagnosis. Correct diagnosis is essential to propose the best treatment, which traditionally consists of surgery, embolization or sclerotherapy. Since a few years, medical treatment has become an important part of multidisciplinary treatment. Genetic and molecular knowledge of vascular anomalies are increasing rapidly and opens the door for a molecular classification of vascular anomalies according to the underlying pathways involved. The main pathways seem to be: PI3K/AKT/mTOR (PIKopathies) and RAS/RAF/MEK/ERK (RASopathies). Knowing the underlying molecular cascades allows us to use targeted medical therapies. The first part of this article aims to review the vascular anomalies seen in the head and neck region and their underlying molecular causes and involved pathways. The second part will propose an overview of the available targeted therapies based on the affected molecular cascade. This article summarizes theragnostic treatments available in vascular anomalies.

Hemangioma-related syndromes

PURPOSE OF REVIEW

There is a growing understanding of complications and anomalies associated with infantile hemangiomas. The current review will discuss recent clinical advances in syndromes associated with segmental hemangiomas, including PHACE and LUMBAR syndrome. In addition, the importance of recognizing visceral hemangiomatosis is highlighted.

RECENT FINDINGS

Ongoing longitudinal studies of PHACE and LUMBAR syndromes associated with segmental infantile hemangiomas have led to improved diagnosis and recommendations for screening for associated anomalies. Characterization of a growing spectrum of associated anomalies as well as better classification of at-risk patients will improve diagnosis and outcomes. In addition, visceral hemangiomatosis recognition and understanding of the potential association with consumptive hypothyroidism will improve initiation of appropriate screening.

SUMMARY

Clinicians should be aware of infantile hemangiomas associated with potential syndromic complications and recognize the need to initiate appropriate work-up. Segmental hemangiomas of the head and neck region may indicate a risk of PHACE syndrome and associated developmental anomalies. Although LUMBAR syndrome is the association of lower body segmental hemangioma with developmental anomalies. Visceral hemangiomas most commonly affect the liver and may be associated with complications such as consumptive hypothyroidism and heart failure.

Two Cases of Oculofaciocardiodental (OFCD) Syndrome due to X-Linked BCOR Mutations Presenting with Infantile Hemangiomas: Phenotypic Overlap with PHACE Syndrome

Background

Oculofaciocardiodental (OFCD) syndrome is due to mutations in BCOR (BCL-6 corepressor). OFCD has phenotypic overlaps with PHACE syndrome (Posterior fossa anomalies, Hemangioma, Arterial anomalies, Cardiac defects, Eye anomalies). Infantile hemangiomas are a key diagnostic criterion for PHACE, but not for OFCD. A previous study reported two cases of infantile hemangiomas in OFCD, but the authors could not exclude chance association.

Case Presentation

We describe two novel cases of female patients (one initially diagnosed with PHACE syndrome), both of whom had infantile hemangiomas. Ophthalmological findings were consistent with oculofaciocardiodental (OFCD) syndrome. Upon genetic testing, these two females were determined to have X-linked BCOR mutations confirming OFCD syndrome diagnoses.

Conclusion

These case reports add support to the hypothesis that infantile hemangiomas may be a feature of OFCD. BCOR may potentially be within a pathway of genes involved in PHACE syndrome and/or in infantile hemangioma formation.

PHACE syndrome: Infantile hemangiomas associated with multiple congenital anomalies: Clues to the cause

Infantile hemangiomas (IH) are the most common vascular tumor of infancy with an estimated 80,000 annual diagnoses in the United States. The genetic mechanisms underlying IH and the related multi-organ birth defect syndromes, PHACE (an acronym for Posterior fossa brain malformations, segmental facial Hemangiomas, Arterial anomalies, Cardiac defects, Eye anomalies, and sternal clefting or supraumbilical raphe) and LUMBAR (an acronym for Lower body hemangiomas, Urogenital anomalies, Myelopathy, Bone deformities, Anorectal malformations/Arterial anomalies, Renal anomalies) remain unsolved. With advances in next generation sequencing (NGS), genomic alterations have been identified in a wide range of vascular anomaly syndromes. We hypothesize that PHACE is a genetic disorder, caused by somatic mutations, likely in cancer genetic pathways. Identification of the genetic etiology will lead to improved diagnosis in PHACE syndrome and development of targeted therapies for IH and related congenital anomalies.

Transient ischemic attack in elderly patient with PHACE syndrome

Background:

Posterior fossa brain malformations, hemangiomas, arterial anomalies, coarctation of the aorta and cardiac defects, and eye abnormalities (PHACE) is a rare congenital anomaly with a broad spectrum of clinical manifestations.

Case Description:

We describe a 75-year-old male with PHACE anomaly, aortic anomaly, malformation of brain, aplastic right carotid artery, and cervical vasculopathy. He presented with a transient ischemic attack with the left hemiparesis, a rare clinical presentation of the PHACE syndrome. He had an uneventful recovery and recently completed a 2-year follow-up after the superficial temporal artery to middle cerebral artery anastomosis.

Conclusion:

PHACE syndrome should be kept in mind, even in individuals of advanced age, in the instance of a TIA, especially in situations which may involve induced hypoperfusion.

Dental root abnormalities in four children with PHACE syndrome

PHACE(S) syndrome is a condition characterized by posterior fossa malformations, hemangiomas, arterial anomalies, cardiac defects, eye abnormalities, sternal cleft, and supraumbilical raphe. We present four children with PHACE(S) syndrome who have absence of or severe malformation of the roots of their permanent first molars (PFMs). Root abnormalities in the children's molars were bilateral and not restricted to the segments affected by cutaneous hemangioma. The reason for root abnormalities is unknown, but given the rarity of these findings in healthy children, it is likely an additional dental manifestation of PHACE syndrome. The absence of functional roots in the PFMs can result in significant consequences. Therefore, we recommend a panoramic dental radiograph during transitional dentition for children with PHACE syndrome to screen for dental root abnormalities.

Genetic investigation of childhood vascular tumor biology reveals pathways for therapeutic intervention

Vascular tumors are neoplasms of endothelial cells, a significant number of which present in childhood. Recent studies have examined the mutational landscape of many subtypes of vascular tumors, identifying mutations primarily within the Ras–mitogen-activated protein kinase (MAPK) pathway and providing a unique opportunity to consider targeted therapeutics. This review will summarize the current understanding of childhood vascular tumor pathobiology.

Distal aortic arch aneurysm in an adult case of PHACE syndrome

A rare case of adult PHACE syndrome with a distal aortic arch aneurysm was treated surgically. The patient had several anomalies including uneven cerebral blood flow, a small left common carotid artery and a narrowed transverse aorta. Under deep hypothermic circulatory arrest, aortic replacement with reconstruction of the left subclavian artery was performed uneventfully. Cystic degeneration of the tunica media was observed in the aneurysm wall.

Structural malformations of the brain, eye, and pituitary gland in PHACE syndrome

PHACE syndrome is the association of segmental facial hemangiomas with congenital arterial, brain, cardiac, and ocular anomalies. Structural brain malformations affect 41-52% of PHACE patients and can be associated with focal neurologic deficits, developmental delays, and/or intellectual disability. To better characterize the spectrum of structural brain and other intracranial anomalies in PHACE syndrome, MRI scans of the head/neck were retrospectively reviewed in 55 patients from the PHACE Syndrome International Clinical Registry and Genetic Repository. All registry patients with a diagnosis of definite PHACE syndrome who had MRI scans of satisfactory quality were included. Of 55 patients, 34 (62%) demonstrated ≥1 non-vascular intracranial anomaly; structural brain malformations were present in 19 (35%). There was no difference in the prevalence of brain anomalies between genders. Brain anomalies were more likely in patients with S1 and/or S2 distribution of facial hemangioma. The most common structural brain defects were cerebellar hypoplasia (25%) and fourth ventricle abnormalities (13%). Dandy-Walker complex and malformations of cortical development were present in 9% and 7%, respectively. Extra-axial findings such as pituitary anomalies (18%) and intracranial hemangiomas (18%) were also observed. Six patients (11%) had anomalies of the globes or optic nerve/chiasm detectable on MRI. Brain malformations comprise a diverse group of structural developmental anomalies that are common in patients with PHACE syndrome. Along with brain malformations, numerous abnormalities of the pituitary, meninges, and globes were observed, highlighting the need for careful radiologic assessment of these structures in the neuroimaging workup for PHACE syndrome.

Prenatal Risk Factors for PHACE Syndrome: A Study Using the PHACE Syndrome International Clinical Registry and Genetic Repository

The cause of PHACE syndrome is unknown. In a study of 218 patients, we examined potential prenatal risk factors for PHACE syndrome. Rates of pre-eclampsia and placenta previa in affected individuals were significantly greater than in the general population. No significant risk factor differences were detected between male and female subjects.

Fetal Alcohol Exposure and PHACE Syndrome: A Case and Autopsy Report

This report describes the clinical, radiologic, and autopsy findings of a newborn with PHACE syndrome (posterior fossa malformations, hemangioma, arterial anomalies, cardiac defects, and eye anomalies) and fetal alcohol spectrum disorder. To our knowledge, the concurrence of these conditions has not been reported in the literature.

Bacurd1/Kctd13 and Bacurd2/Tnfaip1 are interacting partners to Rnd proteins which influence the long-term positioning and dendritic maturation of cerebral cortical neurons

Background

The development of neural circuits within the embryonic cerebral cortex relies on the timely production of neurons, their positioning within the embryonic cerebral cortex as well as their terminal differentiation and dendritic spine connectivity. The RhoA GTPases Rnd2 and Rnd3 are important for neurogenesis and cell migration within the embryonic cortex (Nat Commun 4:1635, 2013), and we recently identified the BTB/POZ domain-containing Adaptor for Cul3-mediated RhoA Degradation family member Bacurd2 (also known as Tnfaip1) as an interacting partner to Rnd2 for the migration of embryonic mouse cortical neurons (Neural Dev 10:9, 2015).

Findings

We have extended this work and report that Bacurd1/Kctd13 and Bacurd2/Tnfaip1 are interacting partners to Rnd2 and Rnd3 in vitro. Given that these genes are expressed during cortical development, we performed a series of in utero electroporation studies in mice and found that disruptions to Bacurd1/Kctd13 or Bacurd2/Tnfaip1 expression impair the long-term positioning of E14.5-born cortical neurons within the postnatal (P17) mouse cerebral cortex. We also find that forced expression of Bacurd1/Kctd13 and Bacurd2/Tnfaip1 alters the branching and dendritic spine properties of layer II/III projection neurons.

Conclusions

We identify Bacurd1/Kctd13 and Bacurd2/Tnfaip1 as interacting partners to Rnd proteins which influence the development of cortical neurons. Their neurodevelopmental functions are likely to be relevant to human brain development and disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13064-016-0062-1) contains supplementary material, which is available to authorized users.

Mosaic Neurocutaneous Disorders and Their Causes

Neurocutaneous disorders are a heterogeneous group of conditions (mainly) affecting the skin [with pigmentary/vascular abnormalities and/or cutaneous tumours] and the central and peripheral nervous system [with congenital abnormalities and/or tumours]. In a number of such disorders, the skin abnormalities can assume a mosaic patterning (usually arranged in archetypical patterns). Alternating segments of affected and unaffected skin or segmentally arranged patterns of abnormal skin often mirror similar phenomena occurring in extra-cutaneous organs/tissues [eg, eye, bone, heart/vessels, lung, kidney and gut]. In some neurocutaneous syndromes the abnormal mosaic patterning involve mainly the skin and the nervous system configuring a (true) mosaic neurocutaneous disorder; or an ordinary trait of a neurocutaneous disorder is sometimes superimposed by a pronounced linear or otherwise segmental involvement; or, lastly, a neurocutaneous disorder can occur solely in a mosaic pattern. Recently, the molecular genetic and cellular bases of an increasing number of neurocutaneous disorders have been unravelled, shedding light on the interplays between common intra- and extra-neuronal signalling pathways encompassing receptor-protein and protein-to-protein cascades (eg, RAS, MAPK, mTOR, PI3K/AKT and GNAQ pathways), which are often responsible of the mosaic distribution of cutaneous and extra-cutaneous features. In this article we will focus on the well known, and less defined mosaic neurocutaneous phenotypes and their related molecular/genetic bases, including the mosaic neurofibromatoses and their related forms (ie, spinal neurofibromatosis and schwannomatosis); Legius syndrome; segmental arrangements in tuberous sclerosis; Sturge-Weber and Klippel-Trenaunay syndromes; microcephaly/megalencephaly-capillary malformation; blue rubber bleb nevus syndrome; Wyburn-Mason syndrome; mixed vascular nevus syndrome; PHACE syndrome; Incontinentia pigmenti; pigmentary mosaicism of the Ito type; neurocutaneous melanosis; cutis tricolor; speckled lentiginous syndrome; epidermal nevus syndromes; Becker's nevus syndrome; phacomatosis pigmentovascularis and pigmentokeratotica; Proteus syndrome; and encephalocraniocutaneous lipomatosis.

Tooth enamel hypoplasia in PHACE syndrome

Individuals with PHACE syndrome (posterior fossa malformations, hemangiomas, arterial anomalies, cardiac defects, eye abnormalities, sternal cleft, and supraumbilical raphe syndrome) have reported dental abnormalities to their healthcare providers and in online forums, but dental involvement has not been comprehensively studied. A study was conducted at the third PHACE Family Conference, held in Milwaukee, Wisconsin, in July 2012. A pediatric dentist examined subjects at enrollment. Eighteen subjects were enrolled. The median age was 4.2 years (range 9 mos-9 yrs; 14 girls, 4 boys). Eleven of 18 patients had intraoral hemangiomas and five of these (50%) had hypomature enamel hypoplasia. None of the seven patients without intraoral hemangiomas had enamel hypoplasia. No other dental abnormalities were seen. Enamel hypoplasia may be a feature of PHACE syndrome when an intraoral hemangioma is present. Enamel hypoplasia increases the risk of caries, and clinicians should refer children with PHACE syndrome to a pediatric dentist by 1 year of age.

Structure and function of nucleotide sugar transporters: Current progress

The proteomes of eukaryotes, bacteria and archaea are highly diverse due, in part, to the complex post-translational modification of protein glycosylation. The diversity of glycosylation in eukaryotes is reliant on nucleotide sugar transporters to translocate specific nucleotide sugars that are synthesised in the cytosol and nucleus, into the endoplasmic reticulum and Golgi apparatus where glycosylation reactions occur. Thirty years of research utilising multidisciplinary approaches has contributed to our current understanding of NST function and structure. In this review, the structure and function, with reference to various disease states, of several NSTs including the UDP-galactose, UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine, GDP-fucose, UDP-N-acetylglucosamine/UDP-glucose/GDP-mannose and CMP-sialic acid transporters will be described. Little is known regarding the exact structure of NSTs due to difficulties associated with crystallising membrane proteins. To date, no three-dimensional structure of any NST has been elucidated. What is known is based on computer predictions, mutagenesis experiments, epitope-tagging studies, in-vitro assays and phylogenetic analysis. In this regard the best-characterised NST to date is the CMP-sialic acid transporter (CST). Therefore in this review we will provide the current state-of-play with respect to the structure–function relationship of the (CST). In particular we have summarised work performed by a number groups detailing the affect of various mutations on CST transport activity, efficiency, and substrate specificity.

Pathogenesis of infantile haemangioma

Haemangioma is a vascular tumour of infancy that is well known for its rapid growth during the first weeks to months of a child's life, followed by a spontaneous but slow involution. During the proliferative phase, the vessels are disorganized and composed of immature endothelial cells. When the tumour involutes, the vessels mature and enlarge but are reduced in number. Fat, fibroblasts and connective tissue replace the vascular tissue, with few, large, feeding and draining vessels evident. Both angiogenesis and vasculogenesis have been proposed as mechanisms contributing to the neovascularization in haemangioma tumours. In recent years, several of the 'building blocks', the cells comprising the haemangioma, have been isolated. Among them are haemangioma progenitor/stem cells, endothelial cells and pericytes. This review focuses on these cell types, and the molecular pathways within these cells that have been implicated in driving the pathogenesis of infantile haemangioma.