The challenges of Proteus syndrome: diagnosis and management

Navigating the complexities of encephalocraniocutaneous lipomatosis: a case series and review

INTRODUCTION

Encephalocraniocutaneous lipomatosis (ECCL) is a rare congenital syndrome with complex skin, eye, and central nervous system (CNS) symptoms. Diagnosis and treatment are challenging due to its rarity and diverse manifestations. It often involves issues like porencephalic cysts, cortical atrophy, and low-grade gliomas in the CNS, resulting in developmental delays. The spinal cord is frequently affected, leading to problems like medullary compression and radiculopathy, causing back pain and sensory/motor deficits. Surgical interventions are reserved for symptomatic cases to address hydrocephalus or alleviate spinal lipomas. This article reviews a case series to assess surgical risks and neurological outcomes.

CASE SERIES

We present a case series ECCL, focusing on the diffuse lipomatosis of the spinal cord and the intricate surgical procedures involved. A multi-stage surgical approach was adopted, with continuous neuromonitoring employed to safeguard motor pathways. We discuss clinical characteristics, imaging studies, and indications for neurosurgical interventions.

DISCUSSION

ECCL is a complex syndrome. Diagnosis is challenging and includes clinical evaluation, neuroimaging, and genetic testing. Treatment targets specific symptoms, often requiring surgery for issues like lipomas or cerebral cysts. Surgery involves laminectomies, spinal fusion, and motor pathway monitoring. Thorough follow-up is crucial due to potential CNS complications like low-grade gliomas. Hydrocephalus occurs in some cases, with endoscopic third ventriculostomy (ETV) preferred over ventriculoperitoneal shunt placement.

CONCLUSION

Neurosurgery for ECCL is for symptomatic cases. ETV is preferred for hydrocephalus, while the treatment for lipoma is based on the presence of symptoms; the follow-up should assess growth and prevent deformities.

Optic nerve compression: a rare ocular manifestation of Proteus syndrome

Proteus syndrome is characterized by progressive, asymmetric, and distorting overgrowth that involves the skeletal, cutaneous, subcutaneous, and nervous systems. We report the case of a 10-year-old girl with Proteus syndrome and a constellation of ocular signs, including congenital glaucoma, myopia, amblyopia, strabismus, megaloglobus, epibulbar tumors, and right retinal detachment. A decrease in left eye visual acuity coupled with significant deterioration in visual evoked potential response over time prompted urgent neuroimaging, which revealed massive overgrowth of the sphenoid bone, with bilateral optic nerve compression due to optic canal stenosis. Successful removal of the roof of the optic canal along its entire course resulted in optic nerve decompression.

Human vascular organoids with a mosaic AKT1 mutation recapitulate Proteus syndrome

Vascular malformation, a key clinical phenotype of Proteus syndrome, lacks effective models for pathophysiological study and drug development due to limited patient sample access. To bridge this gap, we built a human vascular organoid model replicating Proteus syndrome's vasculature. Using CRISPR/Cas9 genome editing and gene overexpression, we created induced pluripotent stem cells (iPSCs) embodying the Proteus syndrome-specific AKTE17K point mutation for organoid generation. Our findings revealed that AKT overactivation in these organoids resulted in smaller sizes yet increased vascular connectivity, although with less stable connections. This could be due to the significant vasculogenesis induced by AKT overactivation. This phenomenon likely stems from boosted vasculogenesis triggered by AKT overactivation, leading to increased vascular sprouting. Additionally, a notable increase in dysfunctional PDGFRβ+ mural cells, impaired in matrix secretion, was observed in these AKT-overactivated organoids. The application of AKT inhibitors (ARQ092, AZD5363, or GDC0068) reversed the vascular malformations; the inhibitors' effectiveness was directly linked to reduced connectivity in the organoids. In summary, our study introduces an innovative in vitro model combining organoid technology and gene editing to explore vascular pathophysiology in Proteus syndrome. This model not only simulates Proteus syndrome vasculature but also holds potential for mimicking vasculatures of other genetically driven diseases. It represents an advance in drug development for rare diseases, historically plagued by slow progress.

Recurrent laryngeal lymphangiomatosis in a patient with Proteus syndrome: A case report

Proteus syndrome is a rare genetic disease characterized by an asymmetrical growth of individual parts of the body and has only been described in single cases. This patient presented with recurrent manifestations of a laryngeal and hypopharyngeal lymphangioma, which were treated with laser surgery, systemic therapy, and sclerotherapy. The reported data depict the diagnosis and treatment in the department of otorhinolaryngology, head and neck surgery of the university hospital Heidelberg from 2019 until May 2023. The recurrent endoscopy of the upper airway was performed using a flexible HD-endoscope and the Visera Elite video tower from Olympus, Hamburg. The 29-year old female patient initially presented in February 2019 with stridor and exertional dyspnea due to a lymphatic malformation of the left larynx and hypopharynx. In April 2019 there was no improvement by sclerotherapy with Picibanil, so that systemic therapy with the PIK3CA inhibitor alpelisib was initiated (03-07/2020) and discontinued due to a high side effect profile. In the course of 2021-2023, three microlaryngoscopies with laser surgical resection and renewed sclerotherapy of the lymphangioma with Picibanil were carried out due to fluctuating findings. After these interventions a stable disease could be established until May 2023. Laser surgical therapy is currently described as the therapy of choice in lymphangiomas in the head and neck region and also showed the highest effectiveness in our patient. In case of airway obstruction in particular, it can bring rapid symptom relief. Alternatively, and with a lower surgical risk, local improvements have been reported by sclerotherapy, which was less effective in the presented case. Rare syndromic diseases require multidisciplinary collaboration. In the case of laryngeal lymphangiomatosis, other treatment options should be considered in addition to surgical excision, especially in the case of recurrence.

Co-occurrence of Proteus syndrome and ventricular tachycardia cardiac arrest in a teenager

Proteus syndrome is an extremely rare overgrowth condition caused by a somatic variant of the AKT1 gene. It can involve multiple organ systems though rarely is there symptomatic cardiac involvement. Fatty infiltration of the myocardium has been described but has not been reported to cause functional or conduction abnormalities. We present an individual with Proteus syndrome who suffered a sudden cardiac arrest.

Phenotypic Features of Cystic Lung Disease in Proteus Syndrome: A Clinical Trial

Rationale: Limited information is available regarding cystic lung disease in Proteus syndrome, a rare overgrowth disorder caused by a somatic activating variant in AKT1. Objectives: To define the phenotype of cystic lung disease in Proteus syndrome. Methods: Medical records, pulmonary function tests, and chest computed tomography of 39 individuals with Proteus syndrome evaluated at a single center were retrospectively reviewed. Lung histopathology from five affected individuals was examined. Results: Cystic lung disease affected 26 (67%) of 39 individuals. The mean age of affected individuals was 17.1 years. The lung cysts varied in size and location. Focal regions of heterogeneous lung parenchyma resembling emphysema were found in 81% of affected individuals. Mass effect was seen in 12% of affected individuals; pneumothorax occurred in one. Dyspnea and respiratory infections were reported by 38% and 35% of affected individuals, respectively. Abnormal pulmonary function and scoliosis were found in 96% of affected individuals. Lung disease progressed in seven of 10 affected individuals, and all five affected individuals younger than 20 years of age had progressive cystic lung disease. Three affected individuals had symptomatic improvement after lung resection. Histopathology showed cystic air space enlargement of varying severity. Conclusions: Cystic lung disease is common in Proteus syndrome and is likely to progress in affected individuals younger than 20 years of age. Screening asymptomatic individuals with Proteus syndrome for cystic lung disease is indicated. Surgical lung resection is a therapeutic option for affected individuals with severe disease. Clinical trial registered with www.clinicaltrials.gov (NCT00001403).

PIK3CA Mutational Analysis in Patients With Macrodactyly

BACKGROUND

Somatic mosaicism for PIK3CA mutations causes various types of growth disorders, which have been summarized under the term PROS (PIK3CA related overgrowth spectrum). Targeted therapy with PI3K inhibitors seems to be a promising alternative for severe PROS cases. Therefore, PIK3CA testing may become more relevant in the future.

METHODS

We report on 14 PROS patients, who had surgery for macrodactyly in the majority of cases. Clinical data were retrieved from the patient's records. Macroscopic and microscopic findings were retrospectively reviewed. Mutational analysis was performed on formalin-fixed paraffin-embedded (FFPE) material.

RESULTS

Patient age ranged from 7 months to 35 years. Five patients showed additional anomalies. One patient had CLOVES syndrome. The majority of the specimens were ray resections characterized by hypertrophic fat tissue. Overall, microscopy was subtle. The abnormal adipose tissue showed lobules exhibiting at least focally fibrous septa. In each case, we could detect a PIK3CA mutation.

CONCLUSION

Histology of affected fat tissue in PROS patients is overall nonspecific. Therefore, mutational analysis represents the key to the diagnosis, especially in unclear clinical cases. We demonstrated that FFPE material is suitable for PIK3CA testing, which can be considered as basis for targeted therapy with PI3K inhibitors.

Chemically-induced osteogenic cells for bone tissue engineering and disease modeling

Cell reprogramming can satisfy the demands of obtaining specific cell types for applications such as tissue regeneration and disease modeling. Here we report the reprogramming of human fibroblasts to produce chemically-induced osteogenic cells (ciOG), and explore the potential uses of ciOG in bone repair and disease treatment. A chemical cocktail of RepSox, forskolin, and phenamil was used for osteogenic induction of fibroblasts by activation of RUNX2 expression. Following a maturation, the cells differentiated toward an osteoblast phenotype that produced mineralized nodules. Bulk and single-cell RNA sequencing identified a distinct ciOG population. ciOG formed mineralized tissue in an ectopic site of immunodeficiency mice, unlike the original fibroblasts. Osteogenic reprogramming was modulated under engineered culture substrates. When generated on a nanofiber substrate ciOG accelerated bone matrix formation in a calvarial defect, indicating that the engineered biomaterial promotes the osteogenic capacity of ciOG in vivo. Furthermore, the ciOG platform recapitulated the genetic bone diseases Proteus syndrome and osteogenesis imperfecta, allowing candidate drug testing. The reprogramming of human fibroblasts into osteogenic cells with a chemical cocktail thus provides a source of specialized cells for use in bone tissue engineering and disease modeling.

Late-onset Proteus syndrome with cerebriform connective tissue nevus and subsequent development of intraductal papilloma

Proteus syndrome (PS) is a rare segmental overgrowth disorder caused by a mosaic activating variant in AKT1. The features of PS are often not present at birth but develop during the first few years of life. We describe a 55-year-old female, whose first symptom of overgrowth, a cerebriform connective tissue nevus, occurred at 19 years of age. We report the identification of the AKT1 c.49G > A p.(Glu17Lys) variant in this progressive lesion, the bony overgrowth, and recurrence after surgical intervention. In the sixth decade of life, this individual developed intraductal papillomas within her right breast which were confirmed to contain the same activating AKT1 variant as the connective tissue nevus. While similar neoplasms have been described in an individual with Proteus syndrome, none has been evaluated for the presence of the AKT1 variant. The tumor also contained two likely pathogenic variants in PIK3R1, c.1392_1403dupTAGATTATATGA p.(Asp464_Tyr467dup) and c.1728_1730delGAG p.(Arg577del). The finding of additional genetic variation putatively affecting the PI3K/AKT pathway in the neoplastic tissue may provide preliminary evidence of a molecular mechanism for tumorigenesis in PS. The late onset of symptoms and molecular characterization of the breast tumor expand the clinical spectrum of this rare disorder.

Precapillary pulmonary arterial hypertension in a patient with Proteus syndrome

Proteus syndrome is a rare progressive multisystem disorder characterized by asymmetric, disproportionate overgrowth of bone, skin, and other tissue types. Molecular pathogenesis has been identified as somatic activating mutations of the AKT1 gene. The presentation of Proteus syndrome is exceptionally variable. Respiratory complications include emphysematous lung disease and predisposition to pulmonary emboli, the latter of which is a significant source of mortality. Pulmonary hypertension due to longstanding hypoxic lung disease as well as chronic thromboembolic events has been observed in this population. In contrast, precapillary pulmonary arterial hypertension in the absence of chronic pulmonary emboli and parenchymal lung disease has not been described in the literature on patients with Proteus syndrome. We report such a case in a young patient with Proteus syndrome, reviewing subsequent management and emphasizing the need for a detailed investigation of dyspnea.

The Role of Interventional Pain Management in Proteus Syndrome: A Case Report

Proteus syndrome (PS) is a rare overgrowth disease process with only a few hundred cases being reported in the literature. Abnormal formation of the vertebral bodies causing scoliosis and spinal stenosis are common features that lead to debilitating pain in these patients. We present a case of a 35-year-old male landscaper with a history of PS causing severe scoliosis and vertebral overgrowth who underwent recurrent sets of multilevel zygapophyseal joint injections for management of his axial back pain. This case illustrates the utility of interventional spinal procedures in patients with progressive pain from PS.

Proteus syndrome with sciatic nerve fibrolipomatous hamartoma: an uncommon finding in a rare disease: report of two cases with literature review

Proteus syndrome is an extremely rare condition, characterized by progressive asymmetric overgrowth of multiple body tissues. Here, we present two cases of Proteus syndrome demonstrating typical clinical and radiological features of Proteus syndrome, in addition to an uncommon fibrolipomatous hamartoma of the sciatic nerve. The first case is a 5-year-old girl who presented with seizures. The patient showed facial dysmorphic features, left head enlargement, kyphoscoliosis, asymmetric overgrowth of the right lower limb, right foot drop, and cribriform connective tissue nevi on the right palm and the right sole. Radiological examinations demonstrated left calvarial hyperostosis, dysplasia of the left cerebral hemisphere, dysregulation of the subcutaneous adipose fat of the body, kyphoscoliosis, and lipoma of the filum terminale. CT of both thighs showed asymmetric soft tissue overgrowth of the right thigh, associated with diffuse enlargement and fatty infiltration of the right sciatic nerve starting from the upper thigh, down to its bifurcation into the tibial and common peroneal nerves. The second case is an 18-year-old girl who presented with left conductive deafness. The patient showed facial dysmorphic features, right head enlargement, asymmetric overgrowth of the right upper limb, kyphoscoliosis, left foot drop, and cribriform connective tissue nevi on the nose and the left foot. Radiological examinations demonstrated right calvarial hyperostosis, left external auditory canal hyperostosis and stenosis, and kyphoscoliosis. CT and MRI of both thighs showed diffuse enlargement of the left sciatic nerve starting from the upper thigh down to the mid-thigh and showing interfascicular adipose tissue proliferation, giving the typical features of nerve lipomatosis.

Treatment strategies for mosaic overgrowth syndromes of the PI3K-AKT-mTOR pathway

INTRODUCTION OR BACKGROUND

Mosaic overgrowth syndromes (OS) are a proteiform ensemble of rare diseases displaying asymmetric overgrowth involving any tissue type, with degrees of severity ranging from isolated malformation to life-threatening conditions such as pulmonary embolism. Despite discordant clinical presentations, all those syndromes share common genetic anomalies: somatic mutations of genes involved in cell growth and proliferation. The PI3K-AKT-mTOR signaling pathway is one of the most prominent regulators of cell homeostasis, and somatic oncogenic mutations affecting this pathway are responsible for mosaic OS. This review aims to describe the clinical and molecular characteristics of the main OS involving the PI3K-AKT-mTOR pathway, along with the treatments available or under development.

SOURCES OF DATA

This review summarizes available data regarding OS in scientific articles published in peer-reviewed journals.

AREAS OF AGREEMENT

OS care requires a multidisciplinary approach relying on clinical and radiological follow-up along with symptomatic treatment. However, no specific treatment has yet shown efficacy in randomized control trials.

AREAS OF CONTROVERSY

Clinical classifications of OS led to frequent misdiagnosis. Moreover, targeted therapies directed at causal mutated proteins are developing in OSs through cancer drugs repositioning, but the evidence of efficacy and tolerance is still lacking for most of them.

GROWING POINTS

The genetic landscape of OS is constantly widening and molecular classifications tend to increase the accuracy of diagnosis, opening opportunities for targeted therapies.

AREAS TIMELY FOR DEVELOPING RESEARCH

OS are a dynamic, expanding field of research. Studies focusing on the identification of genetic anomalies and their pharmacological inhibition are needed.

Proteus syndrome in pregnancy: A case report

Proteus syndrome is a rare, multi-system, genetic syndrome characterised by atypical and excessive growth of skeletal tissue. Clinical presentations include abnormal musculoskeletal growth and cutaneous lesions. Due to its rarity, there have been a limited number of published case reports of Proteus syndrome. This is the first case report on the management of Proteus syndrome in pregnancy. We present the case of a pregnant woman with Proteus syndrome in her first pregnancy in a large teaching hospital and discuss the considerations and challenges faced in her antenatal, intrapartum and postnatal care.

Epidermal Nevi: What Is New

This article reviews the clinical findings of epidermal nevi and their associated syndromes and provides an update on their pathogenic genetic changes as well as targeted therapies detailed to date.

Clinical Phenotype and Bone Biopsy Characteristics in a Child with Proteus Syndrome

Proteus syndrome is a rare genetic disorder, which is characterized by progressive, segmental, or patchy overgrowth of diverse tissues of all germ layers, including the skeleton. Here, we present a 9-year-old girl with a somatic-activating mutation (c.49G > A; p.Glu17Lys) in AKT1 gene in a mosaic status typical for Proteus syndrome. She presented with hemihypertrophy of the right lower limb and a "moccasin" lesion among others. A transiliac bone biopsy was analyzed for bone histology/histomorphometry as well as bone mineralization density distribution (BMDD) and osteocyte lacunae sections (OLS) characteristics based on quantitative backscattered electron imaging. Bone histomorphometry revealed highly increased mineralizing surface (Z-score + 2.3) and mineral apposition rate (Z-score + 19.3), no osteoclasts (Z-score - 2.1), and an increased amount of primary bone in the external cortex. BMDD abnormalities included a decreased mode calcium concentration in cancellous bone (Z-score - 1.7) and an increased percentage of highly mineralized cortical bone area (Z-score + 2.4) compared to reference. OLS characteristics showed several differences compared to reference data; among them, there were the highly increased OLS-porosity, OLS-area, and OLS-perimeter on the external cortex (Z-scores + 6.8, + 4.4 and 5.4, respectively). Our findings suggest that increased bone formation reduced matrix mineralization in cancellous bone while the enhanced amount of primary bone in the external cortex increased the portion of highly mineralized cortical bone and caused OLS-characteristics abnormalities. Our results indicate further that remodeling of primary bone might be disturbed or delayed in agreement with the decreased number of osteoclasts observed in this child with Proteus syndrome.

Ubiquitous expression of Akt1 p.(E17K) results in vascular defects and embryonic lethality in mice

Proteus syndrome is a progressive overgrowth disorder with vascular malformations caused by mosaic expression of the AKT1 c.49G > A, p.(E17K) activating variant which was predicted to cause lethality if expressed ubiquitously. To test that hypothesis, we used the ACTB-Cre gene to activate a conditional Akt1 p.(E17K) allele in the mouse. No offspring that was heterozygous for both Cre and the conditional allele (βA-Akt1WT/flx) was viable. Fewer than expected numbers of βA-Akt1WT/flx embryos were seen beginning at E11.5, but a few survived until E17.5. The phenotype ranged from mild to severe, but generally βA-Akt1WT/flx embryos had fewer visible blood vessels and more hemorrhages than their wild-type littermates, which was suggestive of a vascular abnormality. Examination of E13.5 limb skin showed a primitive capillary network with increased branching complexity and abnormal patterning compared with wild-type skin. By E15.5, wild-type skin had undergone angiogenesis and formed a hierarchical network of remodeled vessels, whereas in βA-Akt1WT/flx embryos, the capillary network failed to remodel. Mural cell coverage of the blood vessels was also reduced in βA-Akt1WT/flx skin compared with that of wild type. Restricting expression of Akt1E17K to endothelial, cardiac or smooth muscle cells resulted in viable offspring and remodeled vasculature and did not recapitulate the βA-Akt1WT/flx phenotype. We conclude that ubiquitous expression of Akt1E17K suppresses remodeling and inhibits the formation of a normal skin vasculature. We postulate that this failure prevents proper circulation necessary to support the growing embryo and that it is the result of interactions of multiple cell types with increased AKT signaling.

Phenotype and Surgical Treatment in a Case of Proteus Syndrome With Craniofacial and Oral Findings

BACKGROUND/AIM

Proteus syndrome is a sporadic disease that is particularly noticeable due to the disproportional growth of body segments. The disease is a genetic mosaic. The mutations can arise from any of the germ layers, an explanation of the very variable phenotype. The aim of this report is to communicate the diagnosis and management of an unusual case of Proteus Syndrome with special attention to oral and craniofacial findings.

CASE REPORT

A 15-year-old patient was referred for surgical treatment of pronounced skull malformations and correction of oral mucosal hyperplasia. Treatment caused significant improvement in facial appearance and oral soft tissue conditions.

CONCLUSION

Surgical measures adapted to the local findings and symptoms can often relieve severe disfigurement of the patient.

A family with Milroy disease caused by the FLT4/VEGFR3 gene variant c.2774 T > A

Background

Milroy disease (MD) is a rare, autosomal-dominant disorder. Variants in the Fms-related tyrosine kinase 4 (FLT4/VEGFR3) gene cause the symptoms of this disease. In this report, we investigated the variant in a large Chinese family with MD.

Methods

We conducted Sanger sequencing of exons 17–26 of FLT4/VEGFR3 (NM_182925.4). We assessed its pathogenicity based on the ACMG criteria and predicted it with an in silico program.

Results

A heterozygous substitution (NM_182925.4 (FLT4/VEGFR3):c.2774 T>A, p. (Val925Glu)) was detected in all patients with MD but not in any healthy controls. The variant was evaluated as pathogenic according to the ACMG criteria and was predicted to be pathogenic using an in silico program.

Conclusions

In this report, we described a large family with MD caused by a missense variant in FLT4/VEGFR3 (NM_182925.4 (FLT4/VEGFR3_v001):c.2774 T>A, p. (Val925Glu)). There are phenotypic heterogeneities among family members, and further research should be conducted to explore the possible reasons.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-00997-w.

Proteus Syndrome: A Rare Case in An Adult Ward

Proteus syndrome is an extremely rare disorder that manifests as an asymmetric, disproportionate overgrowth of any connective tissue, such as bone, fat or epidermal nevi, in a mosaic or patchy pattern. It has an estimated prevalence of less than 1/1,000,000 live births. The diagnosis can be difficult because the phenotypes of the patients are variable. Many individuals develop cutaneous capillary malformation and prominent varicosities (large and complex vascular malformations). Thus, Proteus syndrome patients are at risk of developing deep vein thrombosis and pulmonary embolism. The authors present the case of a patient with Proteus syndrome who was admitted because of pulmonary thromboembolism and presented hypertrophy of the left arm and left hemithorax.

LEARNING POINTS

Proteus syndrome is an extremely rare disorder that manifests as an asymmetric, disproportionate overgrowth of any connective tissue.The diagnosis can be difficult because the phenotypes are variable.It is important to keep in mind the importance of anticoagulation because patients are at risk of developing deep vein thrombosis and pulmonary embolism.

Immature teratoma in an adolescent with Proteus syndrome: A novel association

Proteus syndrome (PS) is a complex disorder characterized by variable clinical findings of overgrowth and tumor susceptibility. This report presents the first known association between PS and an ovarian germ cell tumor in an adolescent with immature teratoma. A review of the diagnosis of PS and associated tumors is included.

Pathogenic postzygotic mosaicism in the tyrosine receptor kinase pathway: potential unidentified human disease hidden away in a few cells

Mutations occurring during embryonic development affect only a subset of cells resulting in two or more distinct cell populations that are present at different levels, also known as postzygotic mosaicism (PZM). Although PZM is a common biological phenomenon, it is often overlooked as a source of disease due to the challenges associated with its detection and characterization, especially for very low-frequency variants. Moreover, PZM can cause a different phenotype compared to constitutional mutations. Especially, lethal mutations in receptor tyrosine kinase (RTK) pathway genes, which exist only in a mosaic state, can have completely new clinical manifestations and can look very different from the associated monogenic disorder. However, some key questions are still not addressed, such as the level of mosaicism resulting in a pathogenic phenotype and how the clinical outcome changes with the development and age. Addressing these questions is not trivial as we require methods with the sensitivity to capture some of these variants hidden away in very few cells. Recent ultra-accurate deep-sequencing approaches can now identify these low-level mosaics and will be central to understand systemic and local effects of mosaicism in the RTK pathway. The main focus of this review is to highlight the importance of low-level mosaics and the need to include their detection in studies of genomic variation associated with disease.

Proteus syndrome: Rare cause of life-threatening haematuria

Proteus syndrome is an extremely rare sporadic hamartomatous condition characterized by random overgrowth of connective, epidermal and bony tissue. Involvement of the genitourinary system in PS is extremely rare and if present, are usually caused by enlarging cysts or neoplasms. Infrequent reports of testicular, renal and bladder involvement have been reported. The involvement of the bladder is predominantly due to vascular malformations with only three previous cases reported in literature. We report the fourth case – one of a 14-year-old male with known Proteus syndrome that presented to the emergency unit with life threatening haematuria. He appeared acutely ill in haemorrhagic shock with a haemoglobin of 4.3 g/dL on index presentation. Initial acute management involved aggressive resuscitation of the patient with intravenous fluids and blood transfusion. Cystoscopy revealed an actively-bleeding extensive venous anomalies of the bladder wall that were successfully-sealed with electrocautery.

Cardiothoracic imaging findings of Proteus syndrome

In this work, we sought to delineate the prevalence of cardiothoracic imaging findings of Proteus syndrome in a large cohort at our institution. Of 53 individuals with a confirmed diagnosis of Proteus syndrome at our institution from 10/2001 to 10/2019, 38 individuals (men, n = 23; average age = 24 years) underwent cardiothoracic imaging (routine chest CT, CT pulmonary angiography and/or cardiac MRI). All studies were retrospectively and independently reviewed by two fellowship-trained cardiothoracic readers. Disagreements were resolved by consensus. Differences between variables were analyzed via parametric and nonparametric tests based on the normality of the distribution. The cardiothoracic findings of Proteus syndrome were diverse, but several were much more common and included: scoliosis from bony overgrowth (94%), pulmonary venous dilation (62%), band-like areas of lung scarring (56%), and hyperlucent lung parenchyma (50%). In addition, of 20 individuals who underwent cardiac MRI, 9/20 (45%) had intramyocardial fat, mostly involving the endocardial surface of the left ventricular septal wall. There was no statistically significant difference among the functional cardiac parameters between individuals with and without intramyocardial fat. Only one individual with intramyocardial fat had mildly decreased function (LVEF = 53%), while all others had normal ejection fraction.

Effect of AKT1 (p. E17K) Hotspot Mutation on Malignant Tumorigenesis and Prognosis

The substitution of the seventeenth amino acid glutamate by lysine in the homologous structural domain of the Akt1 gene pleckstrin is a somatic cellular mutation found in breast, colorectal, and ovarian cancers, named p. Glu17Lys or E17K. In recent years, a growing number of studies have suggested that this mutation may play a unique role in the development of tumors. In this review article, we describe how AKT1(E17K) mutations stimulate downstream signals that cause cells to emerge transformed; we explore the differential regulation and function of E17K in different physiological and pathological settings; and we also describe the phenomenon that E17K impedes tumor growth by interfering with growth-promoting and chemotherapy-resistant AKT1^lowQCC generation, an intriguing finding that mutants may prolong tumor patient survival by activating feedback mechanisms and disrupting transcription. This review is intended to provide a better understanding of the role of AKT1(E17K) in cancer and to inform the development of AKT1(E17K)-based antitumor strategies.

Prenatal diagnosis of Proteus syndrome: Diagnosis of an AKT1 mutation from amniocytes

Proteus syndrome is a mosaic genetic overgrowth disorder caused by a postzygotic, mosaic activating mutation in AKT1. Rare prenatal presentations include segmental tissue overgrowth, and skeletal and CNS anomalies. We present the first report of prenatally diagnosed and molecularly confirmed Proteus syndrome. Prenatal imaging identified megalencephaly, brain and eye malformations, focal soft tissue enlargement, and ambiguous genitalia. Exome sequencing performed on cultured amniocytes demonstrated an AKT1 pathogenic variant consistent with Proteus syndrome, and postnatal examination confirmed the diagnosis. Postnatal Sanger sequencing could not identify the AKT1 pathogenic variant. This case underscores the importance of prenatal exome sequencing on cultured amniocytes for mosaic overgrowth disorders, as well as provides additional information on the prenatal phenotype of Proteus syndrome, and highlights the impact of prenatal diagnosis on postnatal management.

Proteus syndrome of the foot: A case report and literature review

Proteus syndrome (PS) is an extremely rare and sporadic disorder characterized by asymmetric and/or disproportionate overgrowth of limbs, hamartomas, and vascular malformations. The onset of overgrowth usually involves the skin, bone, fat, and other connective tissues in a patchy or mosaic pattern. Partial gigantism of the affected limb or digit is a pathognomonic sign of PS. Thus far, only a few cases of PS have been recorded in the literature. In the present report, a case of PS in a 35-year old woman with classic cerebriform plantar hyperplasia and macrodactyly of the left foot was documented. The clinical and molecular characteristics and differential diagnosis of PS are also discussed in this report.

Allelic heterogeneity of Proteus syndrome

Proteus syndrome is a mosaic disorder that can cause progressive postnatal overgrowth of nearly any organ or tissue. To date, Proteus syndrome has been exclusively associated with the mosaic c.49G > A p.(Glu17Lys) pathogenic variant in AKT1, a variant that is also present in many cancers. Here we describe an individual with severe Proteus syndrome who died at 7.5 yr of age from combined parenchymal and restrictive pulmonary disease. Remarkably, this individual was found to harbor a mosaic c.49_50delinsAG p.(Glu17Arg) variant in AKT1 at a variant allele fraction that ranged from <0.01 to 0.46 in fibroblasts established from an overgrown digit. This variant was demonstrated to be constitutively activating by phosphorylation of AKT(S473). These data document allelic heterogeneity for Proteus syndrome. We recommend that individuals with a potential clinical diagnosis of Proteus syndrome who are negative for the p.(Glu17Lys) variant be tested for other variants in AKT1.

Scoliosis Associated with Proteus Syndrome: Report of 2 Cases and Review of the Literature

BACKGROUND

Proteus syndrome (PS) is a complex genetic disorder, characterized by the sporadic appearance of hamartomatous lesions that follow a mosaic pattern and have a progressive evolution. It affects most of the mesodermal origin tissues, including the bones. Scoliosis is a common manifestation, with great variability and specific peculiarities, but little about it has been published.

CASE DESCRIPTION

Presentation of 2 clinical cases of patients with PS that underwent scoliosis surgery and literature review. Two patients aged 17 years, a girl (patient 1) and a boy (patient 2), both diagnosed with PS, were being followed-up for scoliosis. Patient 1 had a right thoracic curve with a Cobb angle of 69.1°, whereas patient 2 also had a right thoracic curve of 106.8°. In both patients a posterior fusion was performed, associating rib and ponte osteotomies at the level of the apex in patient 2. A minimum 2-year follow-up was done. Both patients had a satisfactory evolution without neurologic or other complications, with a high degree of correction of their curves (Cobb angle 29.2° and 55.6°, respectively). Their total SRS-22 (Scoliosis Research Society Outcomes Questionnaire) score at the last visit was 4.77 and 4.64, respectively.

CONCLUSIONS

Both PS and scoliosis are conditions associated with deformities and physical limitations that decrease the health-related quality of life of these patients. Because of the severity of the spinal deformities and their risk of progression, early diagnosis and prompt treatment is recommended. Despite being highly complex, scoliosis surgery allows a satisfactory deformity correction and consequently improves the health-related quality of life of patients with PS.

A mouse model of Proteus syndrome

Proteus syndrome is a mosaic, progressive overgrowth disorder caused by a somatic activating variant c.49G > A p.(E17K) in AKT1. The presentation in affected individuals is variable, with a diversity of tissues demonstrating abnormalities. Common manifestations include skin and bony overgrowth, vascular malformations (VMs), cysts and benign tumors. We used two methods to create mouse models that had endogenously-regulated mosaic expression of the Proteus syndrome variant. Variant allele fractions (VAFs) ranged from 0% to 50% across numerous tissues in 44 Proteus syndrome mice. Mice were phenotypically heterogeneous with lesions rarely observed before 12 months of age. VMs were the most frequent finding with a total of 69 found in 29 of 44 Proteus syndrome mice. Twenty-eight cysts and ectasia, frequently biliary, were seen in 22 of 44 Proteus syndrome mice. Varying levels of mammary hyperplasia were seen in 10 of 16 female Proteus syndrome mice with other localized regions of hyperplasia and stromal expansion noted in several additional animals. Interestingly, 27 of 31 Proteus syndrome animals had non-zero blood VAF that is in contrast to the human disorder where it is rarely seen in peripheral blood. Identification of variant-positive cells by green fluorescent protein (GFP) staining in chimeric Proteus syndrome mice showed that in some lesions, hyperplastic cells were predominantly GFP/Akt1E17K-positive and showed increased pAKT signal compared to GFP-negative cells. However, hyperplastic mammary epithelium was a mixture of GFP/Akt1E17K-positive and negative cells with some GFP/Akt1E17K-negative cells also having increased pAKT signal suggesting that the variant-positive cells can induce lesion formation in a non-cell autonomous manner.

Clinical report: one year of treatment of Proteus syndrome with miransertib (ARQ 092)

A 20-yr-old man with Proteus syndrome (PS) and somatic mosaicism of the AKT1 c.49G > A p.(E17K) variant had asymmetric overgrowth of the right frontal and facial bones, asymmetric spinal overgrowth with thoracolumbar scoliosis, dilatation of the inferior vena cava, testicular cystadenoma, bilateral knee deformities, macrodactyly, and apparent intellectual disability. Miransertib (ARQ 092) is an oral, allosteric, selective pan-AKT inhibitor initially developed for cancer therapeutics, now being evaluated for the treatment of PS. After baseline evaluation, the patient started unblinded treatment of 10 mg oral miransertib daily (∼5 mg/m²/day), escalated to 30 mg daily (∼15 mg/m²/day), and then to 50 mg daily (∼25 mg/m²/day) after 3 mo of treatment. Adverse events included dry mouth, one episode of gingivostomatitis, and loose, painful dentition due to preexisting periodontal disease, all of which resolved spontaneously. After 11 mo of treatment, the patient reported improved general well-being, increased mobility of the ankle, spine, and hands, a subjective decrease in size of the right facial bone overgrowth, and reduced areas of cerebriform connective tissue nevi on the soles. Whole-body MRI findings were stable without apparent disease progression. We conclude that 1 yr of treatment with miransertib was beneficial in this case.

[Proteus syndrome in the practice of an otorhinolaryngologist: a clinical case]

Described a rare clinical observation of a patient aged 18 years with chronic left-sided otitis media against Proteus syndrome. By this age, the patient underwent a large number of operations regarding the removal of lymphangiomas, hemlimfangiomas, angiokeratitis of the body, as well as several sanitizing surgery on the left ear. A review of domestic and foreign literature showed that this case can be considered unique.

Overgrowth Syndromes-Evaluation, Diagnosis, and Management

Abnormally excessive growth results from perturbation of a complex interplay of genetic, epigenetic, and hormonal factors that orchestrate human growth. Overgrowth syndromes generally present with inherent health concerns and, in some instances, an increased risk of tumor predisposition that necessitate prompt diagnosis and appropriate referral. In this review, we introduce some of the more common overgrowth syndromes, along with their molecular mechanisms, diagnostics, and medical complications for improved recognition and management of patients affected with these disorders.

Genetic predisposition to cancer: Surveillance and intervention

Cancer is one of the leading causes of early mortality for children and adolescents. Identifiable genetic cancer predisposition conditions account for a growing proportion of pediatric and adolescent cancer, likely due to increasing knowledge about various predisposition conditions, more widespread cancer genetic counseling, and available diagnostics. Greater awareness, data-driven surgical intervention and clinical surveillance can help facilitate cancer prevention and early detection at cancer stages more amenable to cure. An extensive literature review of published studies and expert opinion with consensus guidelines are reviewed. Specific syndromes where genetics, imaging and surgical intervention are utilized to benefit affected patients and families are presented. In many tumor predisposition syndromes, the underlying genetic diagnosis is made concurrently, or after, malignancy is identified. Improved recognition of underlying predispositions, along with appropriate surgical interventions and imaging surveillance should lead to increased patient survival.

A dyadic genotype-phenotype approach to diagnostic criteria for Proteus syndrome

Phenotype-based diagnostic criteria were developed for Proteus syndrome in 1999 and updated in 2006. Subsequently, the causative mosaic gene alteration was discovered, the c.49G>A p.E17K variant in AKT1. As well, a number of overlapping overgrowth disorders attributable to mosaic PIK3CA variants have now been characterized, leading to the designation of PIK3CA-related overgrowth spectrum (PROS). Finally, ongoing work to better characterize Proteus syndrome has led to identification of additional features of that disorder that could be useful in diagnostic criteria. We have taken the opportunity of these discoveries to re-evaluate the Proteus syndrome diagnostic criteria. Here we propose a new set of diagnostic criteria that establishes a weighted, point-based system for the phenotypic attributes and then integrates that with the potential molecular test results to result in one of two designations: AKT1-related Proteus syndrome or AKT1-related overgrowth spectrum. A patient whose only manifestation is an AKT1 c.49G>A-positive tumor would receive neither of these designations. Here we review the rational basis of diagnostic criteria and argue that a unitary diagnostic entity is a distinct gene-phenotype dyad and that this should be the model for all mendelian disorders. The gene-alone or phenotype-alone approach is inadequate to rigorously delineate a unitary diagnostic entity.

Thrombosis risk factors in PIK3CA-related overgrowth spectrum and Proteus syndrome

Increased risk of thromboembolism has been recognized in individuals with mosaic overgrowth disorders, Proteus syndrome (PS) and PIK3CA-related overgrowth spectrum (PROS), including Klippel-Trenaunay syndrome and CLOVES syndrome. PS and PROS have distinct, yet overlapping clinical findings and are caused by somatic pathogenic variants in the PI3K/AKT gene signaling pathway. PS is caused by a single somatic activating AKT1 c.49G > A p.E17K variant while PROS can be caused one of multiple variants in PIK3CA. The role of prothrombotic factors, endothelial cell adhesion molecules, and vascular malformations in both PS and PROS have not been previously investigated. A pilot study of prospective clinical and laboratory evaluations with the purposes of identifying potential risk factors for thrombosis was conducted. Doppler ultrasounds and magnetic resonance angiogram/ venography (MRA/MRV) scans identified vascular malformations in PS and PROS that were not appreciated on physical examination. Abnormal D-dimers (0.60-2.0 mcg/ml) occurred in half of individuals, many having vascular malformations, but no thromboses. Soluble vascular endothelial markers, including thrombomodulin, soluble vascular adhesion molecule (sVCAM), soluble intercellular adhesion molecule (sICAM), E-selectin, and P-selectin were significantly higher in PS and PROS compared to controls. However, no single attribute was identified that explained the risk of thrombosis. Predisposition to thrombosis is likely multifactorial with risk factors including chronic stasis within vascular malformations, stasis from impaired mobility (e.g., following surgery), decreased anticoagulant proteins, and effects of AKT1 and PIK3CA variants on vascular endothelium. Based on our findings, we propose clinical recommendations for surveillance of thrombosis in PS and PROS.

Molecular heterogeneity of the cerebriform connective tissue nevus in mosaic overgrowth syndromes

The clinical diagnostic criteria for Proteus syndrome were defined before the discovery of the AKT1 c.49G>A; p.(Glu17Lys) causal variant and used a combination of general and specific phenotypic attributes that could be combined to make a clinical diagnosis. The most heavily weighted specific criterion was the cerebriform connective tissue nevus (CCTN). Here, we describe two individuals with connective tissue nevi (CTNs) and some general attributes of Proteus syndrome who were found to have mosaic PIK3CA variants. CTNs on the soles of individuals with PIK3CA-related overgrowth typically exhibit thickening of the soft tissues with at most a wrinkled surface, but these two patients had firm plaques with ridges and furrows characteristic of CCTNs, which was histologically confirmed in one. These data show that CCTNs are not specific to Proteus syndrome and that clinicians should be cautious in diagnosing individuals with Proteus syndrome based on the CCTN alone. Rather, a complete evaluation should include careful assessment of other attributes of the diagnostic criteria and, whenever possible, genetic analysis of affected tissue.

Overgrowth Syndrome

Large offspring syndrome (LOS) is a fetal overgrowth condition in bovines most often observed in offspring conceived with the use of assisted reproductive technologies (ART). Phenotypes observed in LOS include, overgrowth, enlarged tongues, umbilical hernias, muscle and skeleton malformations, abnormal organ growth and placental development. Although LOS cases have only been reported to be associated with ART, fetal overgrowth can occur spontaneously in cattle (S-LOS). S-LOS refers to oversized calves that are born at normal gestation lengths. ART-induced LOS has been characterized as an epigenetic syndrome, more specifically, a loss-of-imprinting condition. We propose that S-LOS is also a loss-of-imprinting condition.

Giant umbilical cord and hypoglycemia in an infant with Proteus syndrome

Proteus syndrome (PS) is characterized by the progressive, segmental, or patchy overgrowth of the skin, and other tissues. This is the first case report of recurrent severe insulin-independent hypoglycemia in an infant with PS. Somatic p.E17K of AKT1 mutation was confirmed. The patient also had a giant umbilical cord, which has not yet been reported in PS.

First evidence of a therapeutic effect of miransertib in a teenager with Proteus syndrome and ovarian carcinoma

Proteus syndrome (PS) is an ultra-rare disease characterized by progressive, disproportionate, segmental overgrowth caused by a somatic gain-of-function mutation p.Glu17Lys in the oncogene AKT1. The disease has high morbidity and mortality rates due to the increased risk for patients to develop cancer and progressive overgrowth. A teenage patient with severe PS phenotype developed a pelvic recurrence of low-grade serous ovarian carcinoma (LGSOC). Taking into consideration, recent results of the use of AKT inhibitors both in PS and AKT-mutant cancers, we treated the patient on a compassionate basis, with miransertib (ARQ 092), a potent, selective, allosteric AKT inhibitor. Targeted deep sequencing assay of PI3K/AKT pathway genes of the affected overgrowth lesion (cerebriform connective tissue nevus) and the tumor tissues detected the same activating AKT1 mutation in both. Treatment with miransertib led to a complete remission of the cancer and a significant improvement in the patients' everyday life. The treatment is still ongoing at 22 months. This is the first report showing the therapeutic effects of an AKT inhibitor on both benign and malignant tissues that harbor the same pathogenic AKT1 mutation. The present article showed that personalized medicine is feasible in ultra-rare diseases.

Pharmacodynamic Study of Miransertib in Individuals with Proteus Syndrome

Proteus syndrome is a life-threatening segmental overgrowth syndrome caused by a mosaic gain-of-function AKT1 variant. There are no effective treatments for Proteus syndrome. Miransertib is an AKT1 inhibitor that, prior to this study, has been evaluated only in adult oncology trials. We designed a non-randomized, phase 0/1 pilot study of miransertib in adults and children with Proteus syndrome to identify an appropriate dosage starting point for a future efficacy trial using a pharmacodynamic endpoint. The primary endpoint was a 50% reduction in the tissue levels of AKT phosphorylation from biopsies in affected individuals. We also evaluated secondary efficacy endpoints. We found that a dose of 5 mg/m²/day (1/7 the typical dose used in oncology) led to a 50% reduction in phosphorylated AKT (pAKT) in affected tissues from five of six individuals. This dose was well tolerated. Two of the six efficacy endpoints (secondary objectives) suggested that this agent may be efficacious. We observed a decrease in a cerebriform connective tissue nevus and a reduction in pain in children. We conclude that 5 mg/m²/day of miransertib is an appropriate starting point for future efficacy trials and that this agent shows promise of therapeutic efficacy in children with Proteus syndrome.

The Rare Neurocutaneous Disorders: Update on Clinical, Molecular, and Neuroimaging Features

Phakomatoses, also known as neurocutaneous disorders, comprise a vast number of entities that predominantly affect structures originated from the ectoderm such as the central nervous system and the skin, but also the mesoderm, particularly the vascular system. Extensive literature exists about the most common phakomatoses, namely neurofibromatosis, tuberous sclerosis, von Hippel-Lindau and Sturge-Weber syndrome. However, recent developments in the understanding of the molecular underpinnings of less common phakomatoses have sparked interest in these disorders. In this article, we review the clinical features, current pathogenesis, and modern neuroimaging findings of melanophakomatoses, vascular phakomatoses, and other rare neurocutaneous syndromes that may also include tissue overgrowth or neoplastic predisposition.

Characterization of the hepatosplenic and portal venous findings in patients with Proteus syndrome

Proteus syndrome (PS) is a rare disorder caused by a mosaic AKT1 variant that comprises patchy overgrowth of tissues derived from all three germinal layers affecting multiple viscera. We sought to delineate the extent of hepatoportal manifestations in patients with PS. We identified patients with PS who had abdominal imaging from 1989 to 2015 in a natural history study. Imaging was characterized for evidence of focal findings in the liver, spleen, and portal vasculature and for organomegaly. Relevant clinical and laboratory data were compared among those with or without organomegaly. Abdominal imaging was available on 38 patients including 20 who had serial studies. Nine patients had focal hepatic lesions including vascular malformations (VMs). Focal splenic abnormalities were noted in seven patients. Patients without cutaneous VMs did not have visceral VMs. Nine patients had splenomegaly, 12 had portal vein dilation, and 4 had hepatomegaly. There was a weak correlation of portal vein dilation to spleen height ratio (r² = 0.18, p < .05). On laboratory evaluation, hepatic function was normal but there was thrombocytopenia in those with splenomegaly; platelet counts were 179 ± 87K/μL compared to those with normal spleen size at 253 ± 57K/μL (p < .05). Overall, focal hepatosplenic abnormalities occurred in 11 of 38 (29%) patients with PS. Splenomegaly and portal venous dilation were both found in 8 of 38 (21%) patients; however, other than relative thrombocytopenia, there was no evidence of portal hypertension. Although the AKT1-E17K somatic variant is a suspected oncogene, there were no malignant lesions identified in this study.

Clitoromegaly in Childhood and Adolescence: Behind One Clinical Sign, a Clinical Sea

The clitoris is a highly complex organ whose structure has only been clarified in recent years through the use of modern imaging techniques. Clitoromegaly is an abnormal enlargement of this organ. It may be congenital or acquired and is usually due to an excess of androgens in fetal life, infancy, or adolescence. Obvious clitoromegaly in individuals with ambiguous genitalia is easily identifiable, whereas borderline conditions can pass unnoticed. Case reports of clitoromegaly with or without clinical or biochemical hyperandrogenism are quite numerous. In these subjects, a comprehensive physical examination and an accurate personal and family history are needed to investigate the enlargement. We reviewed the literature on the conditions that may be involved in the development of clitoromegaly in childhood and adolescence.