Clinical delineation and natural history of the PIK3CA-related overgrowth spectrum

Urine cell-free DNA is a biomarker for nephroblastomatosis or Wilms tumor in PIK3CA-related overgrowth spectrum (PROS)

Purpose

We set out to facilitate the molecular diagnosis of patients with PIK3CA-related overgrowth spectrum (PROS), a heterogeneous somatic disorder characterized by variable presentations of segmental overgrowth, vascular malformations, skin lesions, and nephroblastomatosis, rare precursor lesions to Wilms tumor (WT). Molecular diagnosis of PROS is challenging due to its mosaic nature, often requiring invasive biopsies.

Methods

Digital droplet polymerase chain reaction was used to analyze tissues including urine, saliva, buccal cells, and blood, from eight patients with PROS. Further analyses were performed on plasma and urine cell-free DNA (cfDNA).

Results

PIK3CA variants were detected in plasma cfDNA at levels up to 0.5% in 50% of tested samples. In addition, high levels of PIK3CA variants in urine cfDNA correlated with a history of nephroblastomatosis compared to patients without renal involvement (p<0.05).

Conclusion

Digital droplet PCR is a sensitive molecular tool that enables low-level variant detection of PIK3CA in various tissue types, providing an alternative diagnostic method. Furthermore, urine cfDNA is a candidate biomarker for nephroblastomatosis in PROS, which may be useful to refine screening guidelines for tumor risk in these patients.

Combined capillary-venous-lymphatic malformations without overgrowth in patients with Klippel-Trénaunay syndrome

OBJECTIVE

Klippel-Trénaunay syndrome (KTS) is described in the literature as a complex syndrome characterized by various combinations of capillary, venous, and lymphatic malformations associated with limb overgrowth. In the first description by Maurice Klippel and Paul Trénaunay, tridimensional bone hypertrophy was believed to be the cause of limb enlargement. The purpose of this study was primarily to assess the presence of real bone hypertrophy as a cause of enlargement of the limb and to underline the rare presence of undergrowth of the affected limb in patients with KTS.

METHODS

A two-center retrospective review including 17 KTS patients with various combinations of capillary, venous, and lymphatic malformation affecting the lower limb was performed. Differences in limb dimension were evaluated clinically. Width and length discrepancy of the affected limb was measured with radiologic imaging.

RESULTS

We found an increase of length in the affected limb in 80% of the patients. The leg length discrepancy varied from 0.2 to 2.6 cm. The median leg length discrepancy was found to be 1.4 cm. Three patients had a reduced length of the affected limb. Girth enlargement of the affected extremity was noticed in 60% of the patients, and 2 of 17 patients had hypotrophy of the involved limb. Hypertrophy (an increase in both length and width) of the bone was found in none of our cases, and the circumferential enlargement of the affected extremity was related only to soft tissue enlargement.

CONCLUSIONS

In the literature, KTS is considered the prototype of overgrowth syndromes associated with complex vascular malformations. The majority of our patients showed limb length increase associated with soft tissue enlargement without an increase of bone width; there were also two patients with limb undergrowth. A real bone overgrowth (an increase in both length and width) was not present in our patients. Therefore, we could consider the absence of real bone hypertrophy as probably a new aspect of such confusing and controversial definitions of KTS. In addition, it would be more accurate to classify KTS patients on the basis of their phenotypic features (type of vascular malformation, types of overgrown tissue) rather than by use of an outdated eponym.

An approach to familial lymphoedema

Lymphoedema is the build-up of lymphatic fluid leading to swelling in the tissues. Most commonly it affects the peripheries. Diagnosis is based on clinical assessment and imaging with lymphoscintigraphy. Treatment is supportive with compression garments, massage, good skin hygiene and prompt use of antibiotics to avoid the complication of cellulitis. Most commonly, lymphoedema occurs as a result of damage to the lymphatic system following surgery, trauma, radiation or infection. However, it can be primary, often associated with a genetic defect that causes disruption to the development of the lymphatic system. Common genetic conditions associated with lymphoedema include Turner syndrome and Noonan syndrome; however, there are numerous others that can be classified based on their clinical presentation and associated features. Herein we discuss how to diagnose and classify the known primary lymphoedema conditions and how best to investigate and manage this group of patients.

Sonographic screening for Wilms tumor in children with CLOVES syndrome

BACKGROUND

CLOVES syndrome is associated with somatic mosaic PIK3CA mutations and characterized by congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and skeletal anomalies. Wilms tumor (WT) is a malignant embryonal renal neoplasm associated with hemihypertrophy and certain overgrowth disorders. After identifying WT in a child with CLOVES, we questioned whether ultrasonographic screening was necessary in these patients.

METHODS

We retrospectively reviewed patients with CLOVES syndrome in our Vascular Anomalies Center at Boston Children's Hospital between 1998 and 2016 to identify those who developed WT. A PubMed literature search was also conducted to find other patients with both conditions.

RESULTS

A total of 122 patients with CLOVES syndrome were found in our database (mean age 7.7 years, range 0-53 years). Four patients developed WT; all were diagnosed by 2 years of age. The incidence of WT in our CLOVES patient population (3.3%) was significantly greater than the incidence of WT in the general population (1/10,000) (P < 0.001). Four additional patients with WT and CLOVES syndrome were identified in our literature review.

CONCLUSION

Patients with CLOVES syndrome have an increased risk of WT. Given the benefits of early detection and treatment, children with CLOVES syndrome should be considered for quarterly abdominal ultrasonography until age 7 years. Screening may be most beneficial for patients under 3 years of age.

Fibroadipose vascular anomaly treated with sirolimus: Successful outcome in two patients

Fibroadipose vascular anomaly (FAVA) is a rare, complex mesenchymal malformation combining fibrofatty replacement of the affected muscles and slow-flow vascular malformation. The condition is characterized by localized swelling, severe pain, phlebectasia, and contracture of the affected limb. Treatment paradigms are not well established for this rare, recently recognized condition. We report two cases of FAVA in which treatment with sirolimus produced rapid, dramatic improvement in pain and quality of life.

A case of congenital lipomatous overgrowth, vascular malformations, epidermal nevi, spinal/skeletal anomalies and/or scoliosis syndrome with lipoatrophy as an important clinical manifestation

Congenital lipomatous overgrowth, vascular malformations, epidermal nevi, spinal/skeletal anomalies and/or scoliosis syndrome is a PIK3CA-related overgrowth spectrum presenting with congenital, asymmetric, disproportionate overgrowth associated with dysregulated adipose tissue, enlarged bony structures, and mixed primarily truncal vascular malformations. We present this case to raise awareness that very thin body habitus (lipoatrophy) contrasting with areas of overgrowth can be an important clinical feature of this syndrome and, if not recognized, can lead to unnecessary investigations.

Somatic PIK3CA mutations in seven patients with PIK3CA-related overgrowth spectrum

Somatic mutations in PIK3CA cause many overgrowth syndromes that have been recently coined the "PIK3CA-Related Overgrowth Spectrum." Here, we present seven molecularly confirmed patients with PIK3CA-Related Overgrowth Spectrum, including patients with Congenital Lipomatous Overgrowth, Vascular Malformations, Epidermal Nevi, Scoliosis/Skeletal and Spinal syndrome, Klippel-Trenaunay syndrome, lymphatic malformation and two with atypical phenotypes that cannot be classified into existing disease categories. The literature on PIK3CA-Related Overgrowth Spectrum, suggests that PIK3CA c.1258T>C; p.(Cys420Arg), c.1624G>A; p.(Glu542Lys), c.1633G>A; p.(Glu545Lys), c.3140A>G; p.(His1047Arg), and c.3140A>T; p.(His1047Leu) can be identified in approximately 90% of patients without brain overgrowth. Therefore, droplet digital polymerase chain reaction targeting these mutation hotspots could be used as the first-tier genetic test on patients with PIK3CA-Related Overgrowth Spectrum who do not have signs of overgrowth in their central nervous system. © 2017 Wiley Periodicals, Inc.

Überwuchssyndrome durch Mutationsmosaike im PI3K-AKT-Signalweg

Es wurde schon länger vermutet, dass segmentale Überwuchssyndrome durch somatische Mutationsmosaike (postzygotische Mutationen) hervorgerufen werden; die ursächlichen genetischen Veränderungen lassen sich aber häufig nur in betroffenem Gewebe nachweisen. Durch den Einsatz der Hochdurchsatzsequenzierung (Next Generation Sequencing, NGS) konnten die genetischen Ursachen von sich segmental manifestierenden Krankheitsbildern in den letzten Jahren zunehmend geklärt werden. Interessanterweise wurden hierdurch bei mehreren Entitäten postzygotische aktivierende Mutationen im Phosphatidylinositol-3-Kinase/AKT/mTOR-Signalweg (PI3K-AKT-Signalweg) als ursächlich identifiziert. Es handelt sich insbesondere um das PIK3CA-assoziierte Überwuchsspektrum (PIK3CA-Related Overgrowth Spectrum, PROS), zu dem neben dem CLOVES-Syndrom (congenital lipomatous overgrowth, vaskuläre Fehlbildungen, epidermale Nävi und Skoliose bzw. Skelettsymptome) und dem MCAP-Syndrom (Megalenzephalie-Kapillarfehlbildungen-Polymikrogyrie) mittlerweile vermutlich auch einige Fälle mit Verdacht auf ein Klippel-Trenaunay-Syndrom gezählt werden können. Beim Proteus-Syndrom dominiert eine spezifische kausale Mutation im AKT1-Gen. Auch wenn somatische Mutationen im PI3K-AKT-Signalweg relativ häufig in sporadischen Tumoren auftreten, stehen der segmentale Überwuchs und weitere Malformationen im Vordergrund des phänotypischen Spektrums der Überwuchssyndrome. Verschiedene klinisch relevante gut- und bösartige Neoplasien kommen allerdings gehäuft vor.

Intraoperative Assessment of Facial Nerve Trunk Width in Early Childhood With Cervicofacial Lymphatic Malformation

Background

Facial nerve damage during head and neck surgery has long been an important issue. However, few publications on the gross anatomy of the facial nerve are available in the young population. The aim of this study was to provide in vivo measurements of the facial nerve trunk during lymphatic malformation (LM) resection and to determine the association between the trunk width and patient- and disease-related variables.

Methods

We conducted a retrospective analysis of 11 consecutive pediatric patients (11 facial nerve trunks) who underwent cervicofacial LM resection. The facial nerve of the affected side was dissected, and its trunk width at bifurcation was measured using calipers under a microscope during the operation.

Results

Eleven patients younger than 6 years were enrolled. The median width of the facial nerve in patients younger than 1 year was 1.15 mm; it was 2.5 mm in those older than 1 year. Trunk width was significantly greater in patients older than 1 year than those younger than 1 year, whereas no statistical significance was found when comparing other age groups. Patient weight was positively correlated with trunk width, whereas LM grade and diameter showed no significant correlation.

Conclusions

The significantly greater width of the facial nerve trunk in LM patients older than 1 year than those younger than 1 year suggests that the age of 1 may be a threshold for facial nerve hypertrophy and growth acceleration. This study provides informative in vivo data to help understand facial nerve characteristics in young patients.

Atypical neurofibromatosis type 1 with unilateral limb hypertrophy mimicking overgrowth syndrome

Neurofibromatosis type 1 (NF1; OMIM 162200), a dominantly inherited multitumor syndrome, results from mutations in the Neurofibromin 1 (NF1) gene. We present the case of a Hungarian woman with the clinical phenotype of NF1 over her whole body and the clinical features of unilateral overgrowth involving her entire left leg. This unusual phenotype suggested either the atypical form of NF1 or the coexistence of NF1 and overgrowth syndrome. Direct sequencing of the genomic DNA isolated from peripheral blood revealed a novel frameshift mutation (c.5727insT, p.V1909fsX1912) in the NF1 gene. Next-generation sequencing of 50 oncogenes and tumour suppressor genes, performed on the genomic DNAs isolated from tissue samples and peripheral blood, detected only wild-type sequences. Based on these results, we concluded that the patient is affected by an unusual phenotype of NF1, and that the observed unilateral overgrowth of the left leg might be a rare consequence of the identified c.5727insT mutation.

AKT/PKB Signaling: Navigating the Network

The Ser and Thr kinase AKT, also known as protein kinase B (PKB), was discovered 25 years ago and has been the focus of tens of thousands of studies in diverse fields of biology and medicine. There have been many advances in our knowledge of the upstream regulatory inputs into AKT, key multifunctional downstream signaling nodes (GSK3, FoxO, mTORC1), which greatly expand the functional repertoire of AKT, and the complex circuitry of this dynamically branching and looping signaling network that is ubiquitous to nearly every cell in our body. Mouse and human genetic studies have also revealed physiological roles for the AKT network in nearly every organ system. Our comprehension of AKT regulation and functions is particularly important given the consequences of AKT dysfunction in diverse pathological settings, including developmental and overgrowth syndromes, cancer, cardiovascular disease, insulin resistance and type 2 diabetes, inflammatory and autoimmune disorders, and neurological disorders. There has also been much progress in developing AKT-selective small molecule inhibitors. Improved understanding of the molecular wiring of the AKT signaling network continues to make an impact that cuts across most disciplines of the biomedical sciences.

Characterization of thrombosis in patients with Proteus syndrome

Patients with overgrowth and complex vascular malformation syndromes, including Proteus syndrome have an increased risk of thromboembolism. Proteus syndrome is a mosaic, progressive overgrowth disorder involving vasculature, skin, and skeleton, and caused by a somatic activating mutation in AKT1. We conducted a comprehensive review of the medical histories and hematologic evaluations of 57 patients with Proteus syndrome to identify potential risk factors for thrombosis. We found that six of ten patients, who were deceased, died secondary to deep venous thrombosis and/or pulmonary embolism. Of the remaining 47 living patients, six had thromboembolic events that all occurred postoperatively and in an affected limb. Eleven of 21 patients had an abnormal hypercoagulable panel including Factor V Leiden heterozygotes, antithrombin III deficiency, positive lupus anticoagulant, or Protein C or S deficiencies. We observed that eight of 17 patients had an abnormal D-dimer level >0.5 mcg/dl, but deep venous thromboses occurred in only four of those with D-dimer >1.0 mcg/dl. We conclude that the predisposition to thrombosis is likely to be multifaceted with risk factors including vascular malformations, immobility, surgery, additional prothrombotic factors, and possible pathophysiologic effects of the somatic AKT1 mutation on platelet function or the vascular endothelium. The D-dimer test is useful as a screen for thromboembolism, although the screening threshold may need to be adjusted for patients with this disorder. We propose developing a registry to collect D-dimer and outcome data to facilitate adjustment of the D-dimer threshold for Proteus syndrome and related disorders, including PIK3CA-Related Overgrowth Spectrum.

Complex Truncal Masses in the Setting of CLOVES Syndrome: Aesthetic and Functional Implications

BACKGROUND

Congenital lipomatous overgrowth, vascular malformations, epidermal nevi, and skeletal abnormalities (CLOVES) is a complex overgrowth syndrome with dramatic aesthetic and functional implications. The truncal masses characteristic of CLOVES syndrome are described as vascular malformations or lipomatous lesions with variable vascular components. Herein, we describe our single-institution experience with surgical excision of CLOVES-related truncal masses and discuss future directions in treatment of these complex anomalies.

METHODS

A single-institution retrospective review was performed for patients diagnosed with CLOVES syndrome. Patients undergoing excision of truncal vascular malformations were included. Outcome measures included perioperative characteristics [estimated blood loss (EBL), specimen size/anatomic location, blood-product requirement], as well as length-of-stay [LOS], and complication profile. Mean follow-up was 23.4 months (range 4.2-44).

RESULTS

Three consecutive patients were reviewed, accounting for 4 surgical operations. One patient underwent two operations for two distinct masses. All lesions were located on the upper back or flank with various degrees of muscular involvement. One patient required no transfusions with an uneventful 2-day hospitalization. The remaining three patients had an EBL ranging from 1500 to 6450 mL, requiring 9-13 units of packed red blood cells and 5-8 units of fresh frozen plasma during LOS (averaging 5 days). Mean weight of resected masses was 6.26 lbs (range 2.04-12 lbs) and mass dimensions ranged between 1778.9 and 15,680 cm³. One patient with recurrence was subsequently treated with a combination of sclerotherapy and rapamycin, leading to significant mass reduction.

CONCLUSIONS

Management of CLOVES syndrome requires a collaborative and multimodal approach. Although surgical debulking is one treatment option, non-invasive medical modalities and sclerotherapy should be considered prior to surgical resection.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

PI3K Signaling in Tissue Hyper-Proliferation: From Overgrowth Syndromes to Kidney Cysts

The members of the PhosphoInositide-3 Kinase (PI3K) protein family are well-known regulators of proliferative signals. By the generation of lipid second messengers, they mediate the activation of AKT/PKB (AKT) and mammalian Target Of Rapamycin (mTOR) pathways. Although mutations in the PI3K/AKT/mTOR pathway are highly characterized in cancer, recent evidence indicates that alterations in the proliferative signals are major drivers of other diseases such as overgrowth disorders and polycystic kidney disease. In this review, we briefly summarize the role of the PI3K/AKT/mTOR pathway in cell proliferation by comparing the effect of alterations in PI3K enzymes in different tissues. In particular, we discuss the most recent findings on how the same pathway may lead to different biological effects, due to the convergence and cooperation of different signaling cascades.

Spectrum of Fat-containing Soft-Tissue Masses at MR Imaging: The Common, the Uncommon, the Characteristic, and the Sometimes Confusing

Fat-containing tumors are the most common soft-tissue tumors encountered clinically. The vast majority of fat-containing soft-tissue masses are benign. Lipomas are the most common benign fat-containing masses and demonstrate a characteristic appearance at magnetic resonance (MR) imaging. Less common benign soft-tissue masses include lipoblastoma, angiolipoma, spindle cell lipoma/pleomorphic lipoma, myolipoma, chondroid lipoma, lipomatosis of nerve, lipomatosis, hibernoma, and fat necrosis. Well-differentiated liposarcomas (WDLPSs)/atypical lipomatous tumors (ALTs) are locally aggressive soft-tissue masses that do not metastasize. Biologically more aggressive liposarcomas include myxoid, pleomorphic, and dedifferentiated liposarcomas. At MR imaging, lipomas typically resemble subcutaneous fat but may contain a few thin septa. The presence of thick, irregular, enhancing septa and nonfatty soft-tissue mass components suggests liposarcoma rather than lipoma. However, benign lipomatous lesions and WDLPS/ALT often have overlapping MR imaging findings. Distinguishing WDLPS/ALT from a benign lipomatous lesion or from fat necrosis at imaging can be challenging and often requires histologic evaluation. We present the spectrum of fat-containing masses, using the World Health Organization classification of adipocytic tumors, with an emphasis on commonly encountered lesions, characteristic MR imaging findings associated with specific tumors, and overlapping MR imaging findings of certain tumors that may require histologic sampling. We also briefly discuss the role of molecular markers in proper characterization and classification of fat-containing soft-tissue masses. (©)RSNA, 2016.

Mosaic Disorders of the PI3K/PTEN/AKT/TSC/mTORC1 Signaling Pathway

Somatic mutations in genes of the PI3K/PTEN/AKT/TSC/mTORC1 signaling pathway cause segmental overgrowth, hamartomas, and malignant tumors. Mosaicism for activating mutations in AKT1 or PIK3CA cause Proteus syndrome and PIK3CA-Related Overgrowth Spectrum, respectively. Postzygotic mutations in PTEN or TSC1/TSC2 cause mosaic forms of PTEN hamartoma tumor syndrome or tuberous sclerosis complex, respectively. Distinct features observed in these mosaic conditions in part reflect differences in embryological timing or tissue type harboring the mutant cells. Deep sequencing of affected tissue is useful for diagnosis. Drugs targeting mTORC1 or other points along this signaling pathway are in clinical trials to treat these disorders.

Prenatal Detection of PIK3CA-related Overgrowth Spectrum in Cultured Amniocytes Using Long-range PCR and Next-generation Sequencing

Mutations in PIK3CA are associated with overgrowth spectrum disorders including excessive growth in some areas of the body and the central nervous system. Alterations in PIK3CA occur as somatic, postzygotic events and confer a mosaic genotype with variability in phenotypic expression being commonly observed. We describe the second reported prenatal diagnosis of a PIK3CA-related overgrowth spectrum disorder. The prenatal ultrasound features in this case enabled the presumptive, prospective diagnosis to be made which was then confirmed by genetic testing. Subsequent parental testing for mutations in PIK3CA demonstrated normal genotypes. Identification of this mutation prenatally enabled prospective information to be provided to the family and facilitated multidisciplinary perinatal management.

Somatic overgrowth disorders of the PI3K/AKT/mTOR pathway & therapeutic strategies

The phosphatidylinositol-3-kinase (PI3K)/AKT/mTOR signaling pathway plays an essential role in regulation of normal cell growth, metabolism, and survival. Somatic activating mutations in the PI3K/AKT/mTOR pathway are among the most common mutations identified in cancer, and have been shown to cause a spectrum of overgrowth syndromes including PIK3CA-Related Overgrowth Spectrum, Proteus syndrome, and brain overgrowth conditions. Clinical findings in these disorders may be isolated or multiple, including sporadic or mosaic overgrowth (adipose, skeletal, muscle, brain, vascular, or lymphatic), and skin abnormalities (including epidermal nevi, hyper-, and hypopigmented lesions), and have the potential risk of tumorigenesis. Key negative regulators of the PI3K-AKT signaling pathway include PTEN and TSC1/TSC2 and germline loss-of function mutations of these genes are established to cause PTEN Hamartoma Tumor Syndrome and Tuberous Sclerosis Complex. Mosaic forms of these conditions lead to increased activation of PI3K and mTOR at affected sites and there is phenotypic overlap between these conditions. All are associated with significant morbidity with limited options for treatment other than symptomatic therapies and surgeries. As dysregulation of the PI3K/AKT/mTOR pathway has been implicated in cancer, several small molecule inhibitors targeting different components of the PI3K/AKT/mTOR signaling pathway are under clinical investigation. The development of these therapies brings closer the prospect of targeting treatment for somatic PI3K/AKT/mTOR-related overgrowth syndromes. This review describes the clinical findings, gene function and pathogenesis of these mosaic overgrowth syndromes, and presents existing and future treatment strategies to reduce or prevent associated complications of these disorders. © 2016 Wiley Periodicals, Inc.

Vascular Stains: Proposal for a Clinical Classification to Improve Diagnosis and Management

Vascular stains are a common reason for consultation in pediatric dermatology clinics. Although vascular stains include all vascular malformations, the term is most often used to refer to capillary malformations, but capillary malformations include a wide range of vascular stains with different clinical features, prognoses, and associated findings. The discovery of several mutations in various capillary malformations and associated syndromes has reinforced these differences, but clinical recognition of these different types of capillary vascular stains is sometimes difficult, and the multitude of classifications and confusing nomenclature often hamper the correct diagnosis and management. From our own experience and a review of the most relevant literature on this topic, we propose categorizing patients with capillary vascular stains into seven major clinical patterns: nevus simplex, port-wine stain, reticulated capillary malformation, geographic capillary malformation, capillary malformation-arteriovenous malformation (CM-AVM), cutis marmorata telangiectatica congenita, and telangiectasia. We also discuss the differential diagnosis of vascular stains as well as other conditions that can closely resemble capillary malformations and thus may potentially be misdiagnosed.

Germline, hematopoietic, mosaic, and somatic variation: interplay between inherited and acquired genetic alterations in disease assessment

Advances in genetic analysis have revealed new complexities in the interpretation of genetic variants. Correct assessment of a genetic variant relies on the clinical context and knowledge of the underlying biology. We outline four scenarios encountered in genetic testing where careful consideration of the origin of genetic variation is required for variant interpretation.

Approach to the Diagnosis of Overgrowth Syndromes

Overgrowth syndromes comprise a group of disorders associated with excessive growth and other features such as facial dysmorphism, developmental delay or intellectual disability, congenital anomalies, neurological problems and an increased risk of neoplasia. Recent advances in understanding the genetic basis of overgrowth syndromes has resulted in a move away from clinical classification to molecular classification of overgrowth syndromes. This review provides a structured clinical approach to patients with this group of disorders and includes most of the currently known overgrowth syndromes.

An Extremely Rare Disorder of Somatic Mosaicism: CLOVES Syndrome

BACKGROUND

CLOVES (Congenital Lipomatous Overgrowth, Vascular malformations, Epidermal nevi Scoliosis, Skeletal, Spinal) syndrome is an extremely rare, complex, non-Mendelian genetic condition with clinical overlap to several other overgrowth syndromes.

PURPOSE

This article shares an interesting case report of the prenatal to postnatal diagnostic course for an infant with this condition.

CASE FINDINGS/RESULTS

It shares prenatal and postnatal images and imaging studies which helped confirm the diagnosis. In addition, the unusual genetic causes of the condition as well as recommended patient-specific management and treatment therapies for this complex condition are discussed.

IMPLICATIONS FOR PRACTICE

Practice implications include honing of physical examination skills and facilitating diagnostic testing required to differentiate CLOVES syndrome from similar conditions. Providers must provide ongoing information and ensure support to families during this diagnostic process. In addition, the majority of care will likely be provided beyond the newborn period. As such, providers must facilitate outpatient follow-up with a number of consultants after hospital discharge.

IMPLICATIONS FOR RESEARCH

Because CLOVES syndrome is so rare, research in this area is limited to a small number of field experts. These experts, however, are well-suited to continue research surrounding disease management and lesion treatment (whether surgical, procedural, or medical) moving forward.

Nephroblastomatosis or Wilms tumor in a fourth patient with a somatic PIK3CA mutation

Wilms tumor and nephroblastomatosis are associated with syndromic conditions including hemihyperplasia. Hemihyperplasia is genetically heterogeneous and may be the result of genomic abnormalities seen in Beckwith-Wiedemann syndrome, mosaic chromosome or genomic abnormalities, or somatic point mutations. Somatic missense mutations affecting the PI3K-AKT-MTOR pathway result in segmental overgrowth and are present in numerous benign and malignant tumors. Here, we report a fourth patient with asymmetric overgrowth due to a somatic PIK3CA mutation who had nephroblastomatosis or Wilms tumor. Similar to two of three reported patients with a somatic PIK3CA mutation and renal tumors, he shared a PIK3CA mutation affecting codon 1047, presented at birth with asymmetric overgrowth, and had fibroadipose overgrowth. Codon 1047 is most commonly affected by somatic mutations in PIK3CA-related overgrowth spectrum (PROS). While the fibroadipose overgrowth phenotype appears to be common in individuals with PIK3CA mutations at codon 1047, individuals with a clinical diagnosis of Klippel-Trenaunay syndrome or isolated lymphatic malformation also had mutations affecting this amino acid. Screening for Wilms tumor in individuals with PROS-related hemihyperplasia may be considered and, until the natural history is fully elucidated in larger cohort studies, may follow guidelines for Beckwith-Wiedemann syndrome, or isolated hemihyperplasia. It is not known if the specific PIK3CA mutation, the mosaic distribution, or the clinical presentation affect the Wilms tumor or nephroblastomatosis risk in individuals with PROS. © 2016 Wiley Periodicals, Inc.

Oral sildenafil as a treatment option for lymphatic malformations in PIK3CA-related tissue overgrowth syndromes

Patients with extensive lymphatic malformations associated with tissue overgrowth syndromes (such as Klippel-Trenaunay syndrome and CLOVES) often pose a therapeutic challenge for physicians. In recent years, it has been suggested that oral sildenafil therapy might be used to treat congenital lymphatic malformations. However, this possible new therapy has not yet been used in patients with lymphatic malformations associated with tissue overgrowth syndromes. A 30-year-old man with extensive capillary-lymphatic malformations of the right leg and thorax, and a tissue overgrowth syndrome caused by a somatic mutation in the PIK3CA gene, was treated with oral sildenafil due to symptoms of pain, dyspnea, and functional impairment. Several weeks after the start of the treatment, the patient reported softening of the lymphatic malformation and a significant improvement of his symptoms and physical condition. So far, sildenafil is still considered a last resort in the treatment of complex treatment-resistant lymphatic malformations. With this case report, we demonstrate that sildenafil could also be an alternative treatment option for lymphatic malformations in patients with syndromes belonging to the PIK3CA-related overgrowth spectrum.

CLOVES syndrome: review of a PIK3CA-related overgrowth spectrum (PROS)

Overgrowth syndromes are characterized by global or localized disproportionate growth associated with other anomalies, including vascular malformations and neurological and/or visceral disorders. CLOVES (Congenital Lipomatous asymmetric Overgrowth of the trunk with lymphatic, capillary, venous, and combined-type Vascular malformations, Epidermal naevi, Scoliosis/Skeletal and spinal anomalies) is an overgrowth syndrome caused by mosaic activating mutation in gene PIK3CA, which gives rise to abnormal PI3K-AKT-mTOR pathway activation. These mutations are responsible for the clinical manifestations of the syndrome, which include low- and high-flow vascular malformations, thoracic lipomatous hyperplasia, asymmetric growth, and visceral and neurological disorders. These common anomalies are illustrated with figures from two personal cases. Identification of the clinical and genetic characteristics of CLOVES syndrome is crucial for the differential diagnosis with other overgrowth syndromes, such as Proteus or Klippel-Trenaunay (K-T) syndromes, and for the therapeutic management of the different anomalies. In this context, a new entity comprising different syndromes with phenotypic mutations in PIK3CA has been proposed, designated PIK3CA-related overgrowth spectrum (PROS), with the aim of facilitating clinical management and establishing appropriate genetic study criteria.

Vascular Lesions

Vascular lesions in childhood are comprised of vascular tumors and vascular malformations. Vascular tumors encompass neoplasms of the vascular system, of which infantile hemangiomas (IHs) are the most common. Vascular malformations, on the other hand, consist of lesions due to anomalous development of the vascular system, including the capillary, venous, arterial, and lymphatic systems. Capillary malformations represent the most frequent type of vascular malformation. IHs and vascular malformations tend to follow relatively predictable growth patterns in that IHs grow then involute during early childhood, whereas vascular malformations tend to exhibit little change. Both vascular tumors and vascular malformations can demonstrate a wide range of severity and potential associated complications necessitating specialist intervention when appropriate. Evaluation and treatment of the most common types of vascular lesions are discussed in this article. [Pediatr Ann. 2016;45(8):e299-e305.].

Molecular Genetics of the PI3K-AKT-mTOR Pathway in Genodermatoses: Diagnostic Implications and Treatment Opportunities

A number of critical signaling pathways are required for homeostatic regulation of cell survival, differentiation, and proliferation during organogenesis. One of them is the PI3K-AKT-mTOR pathway consisting of a cascade of inhibitor/activator molecules. Recently, a number of heritable diseases with skin involvement, manifesting particularly with tissue overgrowth, have been shown to result from mutations in the genes in the PI3K-AKT-mTOR and interacting intracellular pathways. Many of these conditions represent an overlapping spectrum of phenotypic manifestations forming a basis for novel, unifying classifications. Identification of the mutant genes and specific mutations in these patients has implications for diagnostics and genetic counseling and provides a rational basis for the development of novel treatment modalities for this currently intractable group of disorders.

Somatic activating mutations in Pik3ca cause sporadic venous malformations in mice and humans

Venous malformations (VMs) are painful and deforming vascular lesions composed of dilated vascular channels, which are present from birth. Mutations in the TEK gene, encoding the tyrosine kinase receptor TIE2, are found in about half of sporadic (nonfamilial) VMs, and the causes of the remaining cases are unknown. Sclerotherapy, widely accepted as first-line treatment, is not fully efficient, and targeted therapy for this disease remains underexplored. We have generated a mouse model that faithfully mirrors human VM through mosaic expression of Pik3ca(H1047R), a constitutively active mutant of the p110α isoform of phosphatidylinositol 3-kinase (PI3K), in the embryonic mesoderm. Endothelial expression of Pik3ca(H1047R)resulted in endothelial cell (EC) hyperproliferation, reduction in pericyte coverage of blood vessels, and decreased expression of arteriovenous specification markers. PI3K pathway inhibition with rapamycin normalized EC hyperproliferation and pericyte coverage in postnatal retinas and stimulated VM regression in vivo. In line with the mouse data, we also report the presence of activating PIK3CA mutations in human VMs, mutually exclusive with TEK mutations. Our data demonstrate a causal relationship between activating Pik3ca mutations and the genesis of VMs, provide a genetic model that faithfully mirrors the normal etiology and development of this human disease, and establish the basis for the use of PI3K-targeted therapies in VMs.

Overgrowth of the Hand and Upper Extremity and Associated Syndromes

The family of overgrowth disorders affecting the hand and upper extremity constitutes a wide spectrum of clinical phenotypes. These conditions and malformations may be isolated to the upper limb or part of an underlying syndrome. When present, these conditions will challenge even the most experienced hand surgeon. Overlapping clinical presentations and a lack of insight into the fundamental pathogenesis that drives overgrowth in these conditions have created confusion in diagnosis and classification, and have also hampered treatment outcome research. In recent years, advances in molecular biology have identified genetic mutations within the affected tissues of overgrowth patients that appear to mediate these disorders. This may elucidate further understanding, classification, and treatment of these conditions. The purpose of this article is to discuss a range of overgrowth conditions, review some of the newer biological insights, and delineate the general treatment principles.

Molecules in medicine mini-review: isoforms of PI3K in biology and disease

The PI3K lipid kinases are involved in signal transduction and intracellular vesicular traffic, endowing these enzymes with multiple cellular functions and important roles in normal physiology and disease. In this mini-review, we aim to distill from the vast PI3K literature the key relevant concepts for successful targeting of this pathway in disease. Of the eight isoforms of PI3K, the class I PI3Ks have been implicated in the aetiology and maintenance of various diseases, most prominently cancer, overgrowth syndromes, inflammation and autoimmunity, with emerging potential roles in metabolic and cardiovascular disorders. The development of class I PI3K inhibitors, mainly for use in cancer and inflammation, is a very active area of drug development. In 2014, an inhibitor of the p110δ isoform of PI3K was approved for the treatment of specific human B cell malignancies. The key therapeutic indications of targeting each class I PI3K isoform are summarized and discussed.

Somatic Activating PIK3CA Mutations Cause Venous Malformation

Somatic mutations in TEK, the gene encoding endothelial cell tyrosine kinase receptor TIE2, cause more than half of sporadically occurring unifocal venous malformations (VMs). Here, we report that somatic mutations in PIK3CA, the gene encoding the catalytic p110α subunit of PI3K, cause 54% (27 out of 50) of VMs with no detected TEK mutation. The hotspot mutations c.1624G>A, c.1633G>A, and c.3140A>G (p.Glu542Lys, p.Glu545Lys, and p.His1047Arg), frequent in PIK3CA-associated cancers, overgrowth syndromes, and lymphatic malformation (LM), account for >92% of individuals who carry mutations. Like VM-causative mutations in TEK, the PIK3CA mutations cause chronic activation of AKT, dysregulation of certain important angiogenic factors, and abnormal endothelial cell morphology when expressed in human umbilical vein endothelial cells (HUVECs). The p110α-specific inhibitor BYL719 restores all abnormal phenotypes tested, in PIK3CA- as well as TEK-mutant HUVECs, demonstrating that they operate via the same pathogenic pathways. Nevertheless, significant genotype-phenotype correlations in lesion localization and histology are observed between individuals with mutations in PIK3CA versus TEK, pointing to gene-specific effects.

Mouse models of human PIK3CA-related brain overgrowth have acutely treatable epilepsy

Mutations in the catalytic subunit of phosphoinositide 3-kinase (PIK3CA) and other PI3K-AKT pathway components have been associated with cancer and a wide spectrum of brain and body overgrowth. In the brain, the phenotypic spectrum of PIK3CA-related segmental overgrowth includes bilateral dysplastic megalencephaly, hemimegalencephaly and focal cortical dysplasia, the most common cause of intractable pediatric epilepsy. We generated mouse models expressing the most common activating Pik3ca mutations (H1047R and E545K) in developing neural progenitors. These accurately recapitulate all the key human pathological features including brain enlargement, cortical malformation, hydrocephalus and epilepsy, with phenotypic severity dependent on the mutant allele and its time of activation. Underlying mechanisms include increased proliferation, cell size and altered white matter. Notably, we demonstrate that acute 1 hr-suppression of PI3K signaling despite the ongoing presence of dysplasia has dramatic anti-epileptic benefit. Thus PI3K inhibitors offer a promising new avenue for effective anti-epileptic therapy for intractable pediatric epilepsy patients.

DOI:http://dx.doi.org/10.7554/eLife.12703.001

An enzyme called PI3K is involved in a major signaling pathway that controls cell growth. Mutations in this pathway have devastating consequences. When such mutations happen in adults, they can lead to cancer. Mutations that occur in embryos can cause major developmental birth defects, including abnormally large brains. After birth, these developmental problems can cause intellectual disabilities, autism and epilepsy. Children with this kind of epilepsy often do not respond to currently available seizure medications.

There are several outstanding questions that if answered could help efforts to develop treatments for children with brain growth disorders. Firstly, how do the developmental abnormalities happen? Do the abnormalities themselves cause epilepsy? And can drugs that target this pathway, and are already in clinical trials for cancer, control seizures?

Now, Roy et al. have made mouse models of these human developmental brain disorders and used them to answer these questions. The mice were genetically engineered to have various mutations in the gene that encodes the catalytic subunit of the PI3K enzyme. The mutations were the same as those found in people with brain overgrowth disorders, and were activated only in the developing brain of the mice. These mutations caused enlarged brain size, fluid accumulation in the brain, brain malformations and epilepsy in developing mice – thus mimicking the human birth defects. The severity of these symptoms depended on the specific mutation and when the mutant genes were turned on during development.

Next, Roy et al. studied these mice to see if the seizures could be treated using a drug, that has already been developed for brain cancer. This drug specifically targets and reduces the activity of PI3K. Adult mutant mice with brain malformations were treated for just one hour; this dramatically reduced their seizures. These experiments prove that seizures associated with this kind of brain overgrowth disorder are driven by ongoing abnormal PI3K activity and can be treated even when underlying brain abnormalities persist. Roy et al. suggest that drugs targeting PI3K might help treat seizures in children with these brain overgrowth disorders.

DOI:http://dx.doi.org/10.7554/eLife.12703.002

An AKT3-FOXG1-reelin network underlies defective migration in human focal malformations of cortical development

Focal malformations of cortical development (FMCDs) account for the majority of drug-resistant pediatric epilepsy. Postzygotic somatic mutations activating the phosphatidylinositol-4,5-bisphosphate-3-kinase (PI3K)-protein kinase B (AKT)-mammalian target of rapamycin (mTOR) pathway are found in a wide range of brain diseases, including FMCDs. It remains unclear how a mutation in a small fraction of cells disrupts the architecture of the entire hemisphere. Within human FMCD-affected brain, we found that cells showing activation of the PI3K-AKT-mTOR pathway were enriched for the AKT3(E17K) mutation. Introducing the FMCD-causing mutation into mouse brain resulted in electrographic seizures and impaired hemispheric architecture. Mutation-expressing neural progenitors showed misexpression of reelin, which led to a non-cell autonomous migration defect in neighboring cells, due at least in part to derepression of reelin transcription in a manner dependent on the forkhead box (FOX) transcription factor FOXG1. Treatments aimed at either blocking downstream AKT signaling or inactivating reelin restored migration. These findings suggest a central AKT-FOXG1-reelin signaling pathway in FMCD and support pathway inhibitors as potential treatments or therapies for some forms of focal epilepsy.

Molecular analyses of juvenile granulosa cell tumors bearing AKT1 mutations provide insights into tumor biology and therapeutic leads

Juvenile granulosa cell tumors (JGCTs) of the ovary are pediatric neoplasms representing 5% of all granulosa cell tumors (GCTs). Most GCTs are of adult type (AGCTs) and bear a mutation in the FOXL2 gene. The molecular basis of JGCTs is poorly understood, although mutations in the GNAS gene have been reported. We have detected in-frame duplications within the oncogene AKT1 in >60% of the JGCTs studied. Here, to evaluate the functional impact of these duplications and the existence of potential co-driver alterations, we have sequenced the transcriptome of four JGCTs and compared them with control transcriptomes. A search for gene variants detected only private alterations probably unrelated with tumorigenesis, suggesting that tandem duplications are the best candidates to underlie tumor formation in the absence of GNAS alterations. We previously showed that the duplications were specific to JGCTs. However, the screening of eight AGCTs samples without FOXL2 mutation showed the existence of an AKT1 duplication in one case, also having a stromal luteoma. The analysis of RNA-Seq data pinpointed a series of differentially expressed genes, involved in cytokine and hormone signaling and cell division-related processes. Further analyses pointed to the existence of a possible dedifferentiation process and suggested that most of the transcriptomic dysregulation might be mediated by a limited set of transcription factors perturbed by AKT1 activation. Finally, we show that commercially available AKT inhibitors can modulate the in vitro activity of various mutated forms. These results shed light on the pathogenesis of JGCTs and provide therapeutic leads for a targeted treatment.

Overgrowth Syndromes

Numerous multiple malformation syndromes associated with pathologic overgrowth have been described and, for many, their molecular bases elucidated. This review describes the characteristic features of these overgrowth syndromes, as well as the current understanding of their molecular bases, intellectual outcomes, and cancer predispositions. We review syndromes such as Sotos, Malan, Marshall-Smith, Weaver, Simpson-Golabi-Behmel, Perlman, Bannayan-Riley-Ruvalcaba, PI3K-related, Proteus, Beckwith-Wiedemann, fibrous dysplasia, Klippel-Trenaunay-Weber, and Maffucci.

Genitourinary and perineal vascular anomalies in children: A Seattle children's experience

AIMS

We sought to evaluate the initial presentation and diagnosis, to compare presenting symptoms of these anomalies with respect to location, and describe the management course and review the treatment outcomes of vascular anomalies (VA) in genitourinary and perineal area. We described changes in the evaluation and management approach over time.

METHODS

After IRB approval, we reviewed the Vascular Anomalies Program 3,780 patient database from 1998-2013, identifying 85 patients with GUP VA. Demographics, presentation, anatomic location, imaging modalities and treatments were reviewed. For the 76 patients that were managed at our institution, we analyzed data for management approach change over time, duration of follow-up, complications, and treatment outcomes. Using Chi-squared test, we analyzed the treatment eras for any difference in presenting symptoms, or management approach.

RESULTS

From the VAP database, we identified 85 patients with GUP VA. Vascular tumors (VT) were more common than vascular malformations (VM) (62/85, 72.9% vs. 23/85, 27.1%). The 62 patients with VT were subdivided into infantile hemangioma (IH) (49, 79%) and congenital hemangioma (CH) (13, 20.9%). The 23 patients with VM were subdivided into simple (18, 78.2%) and complex (2, 8.7%), and one patient had Klippel-Trenaunay syndrome. Overall, genital VA were more common than perineal (43/85, 54.2% vs. 24/85, 28.2%). None of our patients had urinary involvement. Ultrasound was used in 34% (29/85) of VA patients, the majority were VM (18/23, 78%). Majority of patients were symptomatic with ulceration, pain and bleeding (54/85, 63.5%). Malformations were more complex, presenting as extensive lesions (6/23, 26.1%), which included pelvic extension in 5 (21.7%). Seventy-six patients were managed at our institution. Treatment was utilized more frequently than observation overall (46/76, 60% vs. 30/76, 40%), and more frequently for VM than VT (12/18, 63% vs. 34/58, 57%). After introduction of oral propranolol for treatment of IH in 2010, fewer patients presented with ulceration (p = 0.213), and more were treated with propranolol over procedural therapy (p = 0.157). Overall, complete treatment of these lesions was achieved in 82.9% (63/76), with low complication rate (6/76, 7.9%).

CONCLUSIONS

Evaluation and management of VA is best performed with expert multidisciplinary team at tertiary care center. Imaging studies are mostly used in evaluation of VM. Symptomatic VA involving the perineum and genitalia require therapeutic management. With the introduction of propranolol for treatment of IH, oral therapies were used more often with excellent outcomes. A multidisciplinary approach is essential to treatment innovation, patient-centered therapies and improving therapeutic outcomes.

Mechanistic and therapeutic insights gained from studying rare skeletal diseases

Rare bone diseases account for 5% of all birth defects and can cause significant morbidity throughout patients' lives. Significant progress is being made to elucidate the pathophysiological mechanisms underlying these diseases. This paper summarizes presentation highlights of a workshop on Rare Skeletal Diseases convened to explore how the study of rare diseases has influenced the field's understanding of bone anabolism and catabolism and directed the search for new therapies benefiting patients with rare conditions as well as patients with common skeletal disorders.

Molecular and Functional Characterization of Three Different Postzygotic Mutations in PIK3CA-Related Overgrowth Spectrum (PROS) Patients: Effects on PI3K/AKT/mTOR Signaling and Sensitivity to PIK3 Inhibitors

Background

PIK3CA-related overgrowth spectrum (PROS) include a group of disorders that affect only the terminal portion of a limb, such as type I macrodactyly, and conditions like fibroadipose overgrowth (FAO), megalencephaly-capillary malformation (MCAP) syndrome, congenital lipomatous asymmetric overgrowth of the trunk, lymphatic, capillary, venous, and combined-type vascular malformations, epidermal nevi, skeletal and spinal anomalies (CLOVES) syndrome and Hemihyperplasia Multiple Lipomatosis (HHML). Heterozygous postzygotic PIK3CA mutations are frequently identified in these syndromes, while timing and tissue specificity of the mutational event are likely responsible for the extreme phenotypic variability observed.

Methods

We carried out a combination of Sanger sequencing and targeted deep sequencing of genes involved in the PI3K/AKT/mTOR pathway in three patients (1 MCAP and 2 FAO) to identify causative mutations, and performed immunoblot analyses to assay the phosphorylation status of AKT and P70S6K in affected dermal fibroblasts. In addition, we evaluated their ability to grow in the absence of serum and their response to the PI3K inhibitors wortmannin and LY294002 in vitro.

Results and Conclusion

Our data indicate that patients’ cells showed constitutive activation of the PI3K/Akt pathway. Of note, PI3K pharmacological blockade resulted in a significant reduction of the proliferation rate in culture, suggesting that inhibition of PI3K might prove beneficial in future therapies for PROS patients.