A Comprehensive Review of Syndromic Forms of Obesity: Genetic Etiology, Clinical Features and Molecular Diagnosis

Syndromic obesity refers to obesity occurring with additional clinical findings, such as intellectual disability/developmental delay, dysmorphic features, and congenital malformations. PURPOSE OF REVIEW: To present a narrative review regarding the genetic etiology, clinical description, and molecular diagnosis of syndromic obesity, which is a rare condition with high phenotypic variability and genetic heterogeneity. The following syndromes are presented in this review: Prader-Willi, Bardet-Biedl, Pseudohypoparathyroidism, Alström, Smith-Magenis, Cohen, Temple, 1p36 deletion, 16p11.2 microdeletion, Kleefstra, SIM1-related, Börjeson-Forssman-Lehmann, WAGRO, Carpenter, MORM, and MYT1L-related syndromes. RECENT FINDINGS: There are three main groups of mechanisms for syndromic obesity: imprinting, transcriptional activity regulation, and cellular cilia function. For molecular diagnostic, methods of genome-wide investigation should be prioritized over sequencing of panels of syndromic obesity genes. In addition, we present novel syndromic conditions that need further delineation, but evidences suggest they have a higher frequency of obesity. The etiology of syndromic obesity tends to be linked to disrupted neurodevelopment (central) and is associated with a diversity of genes and biological pathways. In the genetic investigation of individuals with syndromic obesity, the possibility that the etiology of the syndromic condition is independent of obesity should be considered. The accurate genetic diagnosis impacts medical management, treatment, and prognosis, and allows proper genetic counseling.

Establishment of iPSC lines and zebrafish with loss-of-function AHDC1 variants: models for Xia-Gibbs syndrome

Xia-Gibbs syndrome (XGS) is a syndromic form of intellectual disability caused by heterozygous AHDC1 variants, but the pathophysiological mechanisms underlying this syndrome are still unclear. In this manuscript, we describe the development of two different functional models: three induced pluripotent stem cell (iPSC) lines with different loss-of-function (LoF) AHDC1 variants, derived by reprogramming peripheral blood mononuclear cells from XGS patients, and a zebrafish strain with a LoF variant in the ortholog gene (ahdc1) obtained through CRISPR/Cas9-mediated editing. The three iPSC lines showed expression of pluripotency factors (SOX2, SSEA-4, OCT3/4, and NANOG). To verify the capacity of iPSC to differentiate into the three germ layers, we obtained embryoid bodies (EBs), induced their differentiation, and confirmed the mRNA expression of ectodermal, mesodermal, and endodermal markers using the TaqMan hPSC Scorecard. The iPSC lines were also approved for the following quality tests: chromosomal microarray analysis (CMA), mycoplasma testing, and short tandem repeat (STR) DNA profiling. The zebrafish model has an insertion of four base pairs in the ahdc1 gene, is fertile, and breeding between heterozygous and wild-type (WT) animals generated offspring in a genotypic proportion in agreement with Mendelian law. The established iPSC and zebrafish lines were deposited on the hpscreg.eu and zfin.org platforms, respectively. These biological models are the first for XGS and will be used in future studies that investigate the pathophysiology of this syndrome, unraveling its underlying molecular mechanisms.

SCAF4-related syndromic intellectual disability

The causal link between variants in the SCAF4 gene and a syndromic form of intellectual disability (ID) was established in 2020 by Fliedner et al. Since then, no additional cases have been reported. We performed exome sequencing in a 16-year-old Brazilian male presenting with ID, epilepsy, behavioral problems, speech impairment, facial dysmorphisms, heart malformations, and obesity. A de novo pathogenic variant [SCAF4(NM_020706.2):c.374_375dup(p.Glu126LeufsTer20)] was identified. This is the second study reporting the involvement of SCAF4 in syndromic ID, and the description of the patient's clinical features contributes to defining the phenotypic spectrum of this recently described Mendelian disorder.

Polycystic ovary syndrome: clinical and laboratory variables related to new phenotypes using machine-learning models

PURPOSE

Polycystic Ovary Syndrome (PCOS) is the most frequent endocrinopathy in women of reproductive age. Machine learning (ML) is the area of artificial intelligence with a focus on predictive computing algorithms. We aimed to define the most relevant clinical and laboratory variables related to PCOS diagnosis, and to stratify patients into different phenotypic groups (clusters) using ML algorithms.

METHODS

Variables from a database comparing 72 patients with PCOS and 73 healthy women were included. The BorutaShap method, followed by the Random Forest algorithm, was applied to prediction and clustering of PCOS.

RESULTS

Among the 58 variables investigated, the algorithm selected in decreasing order of importance: lipid accumulation product (LAP); abdominal circumference; thrombin activatable fibrinolysis inhibitor (TAFI) levels; body mass index (BMI); C-reactive protein (CRP), high-density lipoprotein cholesterol (HDL-c), follicle-stimulating hormone (FSH) and insulin levels; HOMA-IR value; age; prolactin, 17-OH progesterone and triglycerides levels; and family history of diabetes mellitus in first-degree relative as the variables associated to PCOS diagnosis. The combined use of these variables by the algorithm showed an accuracy of 86% and area under the ROC curve of 97%. Next, PCOS patients were gathered into two clusters in the first, the patients had higher BMI, abdominal circumference, LAP and HOMA-IR index, as well as CRP and insulin levels compared to the other cluster.

CONCLUSION

The developed algorithm could be applied to select more important clinical and biochemical variables related to PCOS and to classify into phenotypically different clusters. These results could guide more personalized and effective approaches to the treatment of PCOS.

Two novel pathogenic variants in MED13L: one familial and one isolated case

BACKGROUND

Genetic variants involving the MED13L gene can lead to an autosomal dominant syndrome characterised by intellectual disability/developmental delay and facial dysmorphism.

METHODS

We investigated two cases (one familial and one isolated) of intellectual disability with speech delay and dysmorphic facial features by whole-exome sequencing analyses. Further, we performed a literature review about clinical and molecular aspects of MED13L gene and syndrome.

RESULTS

Two MED13L variants have been identified [MED13L(NM_015335.5):c.4417C>T and MED13L(NM_015335.5):c.2318delC] and were classified as pathogenic according to the ACMG (American College of Medical Genetics and Genomics) guidelines. One of the variants was present in sibs.

CONCLUSIONS

The two pathogenic variants identified have not been previously reported. Importantly, this is the first report of a familial case of MED13L nonsense mutation. Although the parents of the affected children were no longer available for analysis, their apparently normal phenotypes were surmised from familial verbal descriptions corresponding to normal mental behaviour and phenotype. In this situation, the familial component of mutation transmission might be caused by gonadal mosaicism of a MED13L mutation in a gonad from either the father or the mother. The case reports and the literature review presented in this manuscript can be useful for genetic counselling.

Haptoglobin levels are influenced by Hp1-Hp2 polymorphism, obesity, inflammation, and hypertension in type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an inflammatory condition associated to obesity and increased oxidative stress. Haptoglobin (Hp) is an acute phase reactant that scavenges extracorpuscular hemoglobin from circulation and prevents heme-iron oxidative damage.

OBJECTIVE

To assess the association between Hp levels and Hp1-Hp2 gene polymorphism and clinical and laboratory parameters in patients with T2DM.

METHODS

The study sample consisted of 102 T2DM patients and 62 controls. Hp plasma levels were measured using an ELISA assay, and Hp genotyping was performed using a specific two-step allelic polymerase chain reaction.

RESULTS

Hp levels were higher in T2DM patients as compared to controls (p=0.005). T2DM patients with high blood pressure had higher Hp levels than patients without this comorbidity (p=0.021). Obese T2DM patients had higher Hp levels as compared to obese controls (p=0.009) and to non-obese T2DM patients (p=0.003). The Hp1-Hp1 genotype was showed to be associated to T2DM according to additive (OR=3.038, 95% CI 1.127-8.192; p=0.036) and dominant model (OR=0.320, 95% CI 0.118-0.839; p=0.010), but Hp2 allele carriers contributed with higher Hp levels in T2DM as compared to controls. Waist circumference (p=0.002), BMI (p=0.001), and IL-6 (p=0.012), and hs-CRP (p=0.001) levels positively correlated with Hp levels in the T2DM group.

CONCLUSION

These results suggest that Hp levels are influenced by Hp1-Hp2 polymorphism, obesity, inflammatory status, and high blood pressure in T2DM.

Development of esthetic prosthesis for a patient with severe stigmatizing facial lesions due to cancer: a pilot study

PURPOSE

Severe physical facial deformities due to surgical interventions can have significant psychosocial consequences to patient's relationships with friends and family and thus, has a considerable impact on their quality of life. We have developed a 3D prosthesis for a 56-year-old woman diagnosed with epidermoid carcinoma at the right hemiface, to improve her quality of life.

METHODS

The patient started radiotherapy with modulated intensity. To deal with the advance of the process, a maxilectomy of supra structure with modified radical cervical emptying on the right hemiface was performed. Reconstruction of areas surgically affected by the displacement of islands of skin and muscle (flaps) from healthy regions was initiated. Although the procedure occurred without intercurrences, the patient developed necrosis and loss of the myocutaneous flap. After the removal of the flap, the esthetic result of the treatment was evident causing exposure of subcutaneous and granulation tissues.

RESULTS

A computational model was used to develop a 3D structure of the affected area and then used to construct the prosthesis. The prosthesis was applied over the affected area, and the patient was able see her face on the mirror for the first time in years. The patient was grateful and hopeful.

CONCLUSION

We have found that the application of this new technology greatly improves the social interaction of patients with deformities due to surgical interventions.

Microparticles: Inflammatory and haemostatic biomarkers in Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS) is associated with a chronic low-grade inflammation and predisposition to hemostatic and atherosclerotic complications. This case-control study evaluated the microparticles (MPs) profile in patients with the PCOS and related these MPs to clinical and biochemical parameters. MPs derived from platelets (PMPs), leuckocytes (LMPs) and endothelial cells (EMPs) were evaluated, as well as MPs expressing tissue factor (TFMPs), by flow cytometry, comparing women with PCOS (n = 50) and a healthy control group (n = 50). PCOS women presented increased total MPs, PMPs, LMPs and EMPs levels when compared to control group (all p < 0.05). TFMPs was similar between the groups (p = 0.379). In conclusion, these MPs populations could be useful biomarkers for association with thrombosis and cardiovascular disease in PCOS women.