OBJECTIVE: To demonstrate a high-yield molecular diagnostic workflow for lateralized overgrowth (LO), a congenital condition with abnormal enlargement of body parts, and to classify it by molecular genetics. and STUDY DESIGN: We categorized 186 retrospective cases of LO diagnosed between 2003 and 2023 into suspected Beckwith-Wiedemann spectrum (BWSp), PIK3CA-Related Overgrowth Spectrum (PROS), vascular overgrowth (VO) , or isolated (ILO), based on initial clinical assessments, to determine the appropriate first-tier molecular tests and tissue for analysis. Patients underwent testing for 11p15 epigenetic abnormalities or somatic variants in genes related to PI3K/AKT/mTOR, vascular proliferation, and RAS-MAPK cascades using blood or skin DNA. For cases with negative initial tests, a sequential cascade molecular approach was employed to improve diagnostic yield.
RESULTS: This approach led to a molecular diagnosis in 54% of cases, 89% of cases consistent with initial clinical suspicions and 11% reclassified. BWSp was the most common cause, with 43% of cases exhibiting 11p15 abnormalities. PROS had the highest confirmation rate, with 74% of clinically diagnosed patients showing a PIK3CA variant. VO demonstrated significant clinical overlap with other syndromes. Molecular diagnosis of ILO proved challenging, with only 21% of cases classifiable into a specific condition.
CONCLUSIONS: Despite, LO is underdiagnosed from a molecular viewpoint and to date has had no diagnostic guidelines, which would be crucial for addressing potential cancer predisposition, enabling precision medicine treatments, or guiding management. This study sheds light on the molecular etiology of LO, highlighting the importance of tailored diagnostic approach and of selecting appropriate testing to achieve the highest diagnostic yield.

Hemihyperplasia and hemihypoplasia result in leg length discrepancy (LLD) by causing skeletal asymmetry. Beckwith-Wiedemann syndrome (BWS) and Silver-Russell syndrome (SRS) are opposite growth-affecting disorders caused by opposite epigenetic alterations at the same chromosomal locus, 11p15, to induce hemihyperplasia and hemihypoplasia, respectively. Because of their somatic mosaicism, BWS and SRS show a wide spectrum of clinical phenotypes. We evaluated the underlying epigenetic alterations and potential epigenotype-phenotype correlations, focusing on LLD, in a group of individuals with isolated hemihyperplasia/hemihypoplasia.
We prospectively collected paired blood-tissue samples from 30 patients with isolated hemihyperplasia/hemihypoplasia who underwent surgery for LLD. Methylation-specific multiplex-ligation-dependent probe amplification assay (MS-MLPA) and bisulfite pyrosequencing for differentially methylated regions 1 and 2 (DMR1 and DMR2) on chromosome 11p15 were performed using the patient samples. Samples from patients showing no abnormalities in MS-MLPA or bisulfite pyrosequencing were analyzed by single nucleotide polymorphism (SNP) microarray and CDKN1C Sanger sequencing. We introduced a metric named as the methylation difference, defined as the difference in DNA methylation levels between DMR1 and DMR2. The correlation between the methylation difference and the predicted LLD at skeletal maturity, calculated using a multiplier method, was evaluated. Predicted LLD was standardized for stature. Ten patients (33%) showed epigenetic alterations in MS-MLPA and bisulfite pyrosequencing. Of these, six and four patients had epigenetic alterations related to BWS and SRS, respectively. The clinical diagnosis of hemihyperplasia/hemihypoplasia was not compatible with the epigenetic alterations in four of these ten patients. No patients showed abnormalities in SNP array or their CDKN1C sequences. The standardized predicted LLD was moderately correlated with the methylation difference using fat tissue (r = 0.53; p = 0.002) and skin tissue (r = 0.50; p = 0.005) in all patients.
Isolated hemihyperplasia and hemihypoplasia can occur as a spectrum of BWS and SRS. Although the accurate differentiation between isolated hemihyperplasia and isolated hemihypoplasia is important in tumor surveillance planning, it is often difficult to clinically differentiate these two diseases without epigenetic tests. Epigenetic tests may play a role in the prediction of LLD, which would aid in treatment planning.

BACKGROUND: Primary intestinal lymphangiectasia is an exceedingly rare disorder. Epidemiology is unknown. It usually presents with lower extremity swelling, diarrhea, ascites, and protein-losing enteropathy. Since the pathogenesis of edema is usually due to hypoalbuminemia; both extremities are typically involved. The edema can rarely be due to abnormal lymphatic circulation, causing lymphedema, which usually involves both extremities as well. Diagnosis is made by the constellation of clinical, biochemical, endoscopic, and histological findings. Treatment involves dietary modification, to reduce lymphatic dilation in response to dietary fat. Other pharmacologic (e.g., octreotide) and replacement measures may be indicated as well. The most serious long-term complication is intestinal lymphoma. Herein is a case of Primary intestinal lymphangiectasia presenting with unilateral lower limb swelling.
METHODS: A 4-year-old boy presents with left foot swelling since the age of 4 months, in addition to intermittent diarrhea, and abdominal swelling. The foot swelling had been evaluated by different health care professionals in the past, and was mislabeled as either cellulitis, or congenital hemihyperplasia. Physical examination revealed mild ascites, and a non-pitting foot edema with a positive Stemmer\'s sign (lymphedema). Blood work revealed hypoalbuminemia (albumin 2 g/dl), and hypogammaglobulinemia. Endoscopy showed dilated lacteals throughout the duodenum. Histopathologic examination revealed massively dilated lamina propria lymphatics in the duodenal biopsies. The patient was diagnosed with primary intestinal lymphangiectasia. He was treated with high-protein and low-fat diet, and supplemental formula high in medium chain triglycerides. On follow-up, the patient\'s diarrhea completely resolved, and his ascites and edema improved significantly.
CONCLUSIONS: The presence of unilateral lower limb edema should not preclude the diagnosis of systemic disorders, and a high index of suspicion is required in atypical presentations. A good knowledge about Primary intestinal lymphangiectasia manifestations, and physical examination skills to differentiate edema or lymphedema from tissue overgrowth can significantly aid in the diagnosis.

To provide information on evolution over time of leg length discrepancy in patients with syndromic and isolated lateralized overgrowth.
This retrospective study investigates leg length discrepancy longitudinally in 105 patients with lateralized overgrowth either isolated (n = 37) or associated with Beckwith-Wiedemann spectrum (n = 56) or PIK3CA-related overgrowth spectrum (n = 12). Discrepancy was measured by standard methods and categorized as minor, mild, severe, and critical, based on the thresholds of 1, 2 and 5, respectively.
The period of observation from diagnosis was 1.7 ± 2.6 to 9.0 ± 6.0 years. Leg length discrepancy was 11.0 ± 7.2 mm at diagnosis and 17.1 ± 14.4 mm at last visit. Both final leg length discrepancy and change over time were correlated with discrepancy at diagnosis (r2 = 0.45, P < .001 and r2 = 0.05, P = .019, respectively). Among minor leg length discrepancy at diagnosis, 47.5% remained minor, 40.0% become mild, and 12.5% severe. Among patients with discrepancy classified as severe at diagnosis, 84.6% remained severe and 15.4% evolved to critical. The isolated lateralized overgrowth group showed a milder evolution over time compared with Beckwith-Wiedemann spectrum and PIK3CA-related overgrowth spectrum groups. Among patients with Beckwith-Wiedemann, those with paternal chromosome 11 uniparental disomy had more severe leg length discrepancy at diagnosis and evolution over time.
Leg length discrepancy associated with isolated or syndromic lateralized overgrowth tends to worsen with growth and correlates with discrepancy at first observation. Among the genotypic groups, isolated lateralized overgrowth tends to have a milder evolution, whereas Beckwith-Wiedemann spectrum predisposes to a more severe outcome, especially if associated with paternal chromosome 11 uniparental disomy genotype.

Lateralized overgrowth (LO), or segmental overgrowth, is defined as an increase in growth of tissue (bone, muscle, connective tissue, vasculature, etc.) in any region of the body. Some overgrowth syndromes, characterized by both generalized and lateralized overgrowth, have been associated with an increased risk of tumor development. This may be due to the underlying genetic and epigenetic defects that lead to disrupted cell growth and proliferation pathways resulting in the overgrowth and tumor phenotypes. This chapter focuses on the four most common syndromes characterized by LO: Beckwith-Wiedemann spectrum (BWSp), PIK3CA-related overgrowth spectrum (PROS), Proteus syndrome (PS), and PTEN hamartoma tumor syndrome (PHTS). These syndromes demonstrate variable risks for tumor development in patients affected by LO, and we provide a comprehensive literature review of all common tumors reported in patients diagnosed with an LO-related disorder. This review summarizes the current data on tumor risk among these disorders and their associated tumor screening guidelines. Furthermore, this chapter highlights the importance of an accurate diagnosis when a patient presents with LO as similar phenotypes are associated with different tumor risks, thereby altering preventative screening protocols.

UNASSIGNED: Isolated or congenital hemihypertrophy is a rare disorder characterized by asymmetric overgrowth of one side of the body. This article describes the protocol and preliminary results of a lateral body asymmetry (hemihypertrophy) screening procedure performed in healthy adolescents in a multicenter study. The reported incidence of hemihypertrophy varies between different publications and standardized protocols are needed to improve research in this area.
UNASSIGNED: Our screening program is taking place in Australia, Israel, Mexico, Ukraine and USA. Procedure includes two steps: (1) \"three measurements - three questions\" screening, or assessment of face, palms, and shins; (2) in-depth assessment of selected cases in order to exclude localized, lesional, and syndrome-related cases as well as body asymmetry within normative range and to select suspected cases of isolated hemihypertrophy. This step includes measurements of various anatomical regions and a detailed questionnaire.
UNASSIGNED: At this stage, the screening procedure is completed and the selected participants are advised to refer to medical institutions for further clinical and genetic follow up to exclude possible tumors and other accompanying disorders.
UNASSIGNED: We present an easy-to-use selection tool to identify children with suspected IH, which results in the selection of the risk group that may benefit from referral to a pediatrician and a clinical geneticist.

OBJECTIVE: The reported incidence of isolated hemihyperplasia (IH) has a very wide range (from 1:13,000 to 1:86,000 live births) and further clarification is needed. We hypothesized that a survey of the birth prevalence of IH among newborn infants may underestimate the incidence of IH by overlooking late-onset cases.
METHODS: The prospective international multicenter study utilized the two-steps selection tool for an anonymous survey of volunteers of 15-18 years old. The initial step was \"three measurements-three questions\" screening, or \"face-palms-calves survey\". The subsequent step was an in-depth assessment of selected cases to exclude localized, lesional and syndrome-related cases as well as body asymmetry within normative range and to select suspected cases of IH. This step included measurements of various anatomical regions and a subsequent questionnaire. The participants that were selected in a risk group were advised to refer to medical institutions for clinical, genetic and instrumental investigation.
RESULTS: Out of 6000 of selected participants (male, M 3452, female, F 2548), 229 (3.82%) were selected for detailed investigation and 57 (0.95%) were assigned to the risk group. Only 36 of them were actually referred to medical institutions and in two cases the diagnosis of IH was confirmed.
CONCLUSIONS: Our survey indicated the prevalence of IH at the age of adolescence as approximately 1:3000. While IH is a hereditary genetic disorder, it may not be detected in newborns and infants and the true prevalence of the disease can be estimated if older age children are screened.

BACKGROUND: Overgrowth syndromes are known as a heterogeneous group of conditions characterized by a generalized or segmental, symmetric or asymmetric, overgrowth that may involve several tissues. These disorders, which present a wide range of phenotypic variability, are often caused by mosaic somatic mutations in the genes associated with the PI3K/AKT/mTOR cellular pathway, a signaling cascade that plays a key role in cellular growth. Overgrowth syndromes are frequently misdiagnosed. Given that they are also associated to an increased oncologic risk, it is important to distinguish the clinical characteristic of these disorders since the first months of life.
METHODS: We report the case of a seven-year-old male child with macrocephaly and right lateralized overgrowth, reported from birth. The patient arrived to our attention after an initial diagnosis of isolated benign macrocephaly was formulated at the age of 12 months. Afterwards, the child presented a moderate intellectual disability and pain episodes at right lower limb. We repeated a brain Magnetic Resonance Imaging that revealed ventriculomegaly, cerebellar tonsillar ectopia, a markedly thick corpus callosum, and white matter abnormalities. The diagnosis of segmental overgrowth syndrome was formulated according to the clinical presentation and confirmed by the finding of the variant c.2740G > A in the gene PIK3CA presented in somatic mosaicism.
CONCLUSIONS: Our patient is the first children with the c.2740G > A variant in PIK3CA gene reported in Italy. We underline the importance of the genotype-phenotype correlation in the diagnostic process of overgrowth syndromes and emphasize the strict correlation between the mutation c.2740G > A in the PIK3CA gene and the Megalencephaly-Capillary Malformation syndrome phenotype.

OBJECTIVE: The purpose of this study was to evaluate treatment and surgical outcomes of patients of Beckwith-Wiedemann Syndrome (BWS) treated at a tertiary children\'s hospital.
METHODS: A retrospective review of infants evaluated at Texas Children\'s Hospital for BWS from August 2000 to December 2016 was performed. Data collected included demographic information, clinical presentation, genetic evaluation, fetal imaging, operative treatment, and outcomes.
RESULTS: Forty-seven children with a diagnosis of BWS were identified. Sixty-four percent (n=30) had a genetic mutation in an imprinting domain of chromosome 11p15. Thirty-two patients (68%) underwent at least one operation related to BWS with a median of 2 [range: 0-8] surgical procedures per patient. Sixteen underwent omphalocele repair, 12 had partial glossectomies-, 7 underwent surgeries related to hemihypertrophy, and 6 had resection of an embryonal tumor (two adrenal cortical adenoma, one Wilms\' tumor, two hepatoblastoma). Overall, survival was 100% with feeding difficulty (47%) being the most frequent complication.
CONCLUSIONS: A substantial number of patients with Beckwith-Wiedemann Syndrome will require surgery. However, overall outcomes are similar between those that require surgery and those that do not.
METHODS: Level III.

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.