Research Progress of Monogenic Mutation in the Pathogenesis of Steroid-Resistant Nephrotic Syndrome / 罕见病研究

Steroid-resistant nephrotic syndrome (SRNS) is the second cause of chronic kidney disease in children. The SRNS has high risk of rapid progression to end-stage renal disease. With the advancement of high-throughput sequencing technology, more than 70 monogenic mutation having the Mendelian inheritance patterns are identified to be associated with SRNS. Most of these genes are involved in podocyte function. Accurate diagnosis of monogenic mutation in SRNS patients helps with guiding clinical treatment protocols and genetic counseling, avoiding the excessive use of steroids/immunosuppressive therapy, and opening up possibilities for targeted therapies in SRNS patients. In this article, our research team summarizes and generalizes the molecular mechanisms, genetic testing, and specific treatment for the major types of monogenic mutations associated with SRNS.

Advances of Dupilumab in Treating Rare Monogenic Inherited Skin Diseases / 罕见病研究

Monogenic inherited skin diseases are a group of clinically rare diseases that include nearly 1000 phenotypically distinct disorders. Through the concerted efforts of researchers in dermatological sciences and related disciplines worldwide, many advances have been made in the etiology and pathogenesis of these diseases in the last 30 years. However, it is important to note that the treatment of the majority of monogenic inherited skin diseases remains a challenge for clinicians. Dupilumab is a fully human monoclonal IgG4 antibody that specifically binds to the α subunit of the IL-4 receptor, thereby inhibiting the IL-4 and IL-13 signaling pathway. It was first approved for the treatment of moderate-to-severe atopic dermatitis (AD) and has been used worldwide. In recent years, the drug has been successfully used to treat some monogenic inherited skin diseases with AD-like clinical manifestations, such as hyper-IgE syndrome and Netherton syndrome, with good efficacy. The drug was later tried for the treatment of other monogenic inherited skin diseases, such as Hailey-Hailey syndrome and epidermolysis bullosa pruriginosa, where it was also proven to be effective. In this paper, we review literature reports related to dupilumab for the treatment of monogenic inherited skin diseases in recent years, focusing on its efficacy, safety and possible therapeutic mechanisms. We aim to provide a possible scientific basis for the future application of this drug in the field of rare monogenic inherited skin diseases.

A case of diabetes mellitus with glucokinase regulator gene mutation misdiagnosed as type 1 diabetes / 中华内分泌代谢杂志

We report a case of a female teenage with monogenic diabetes mellitus caused by glucokinase regulator (GCKR) gene mutation who presented with diabetic ketosis and misdiagnosed as type 1 diabetes. The patient was treated with insulin for 3 years since diagnosis. The islet function was well preserved, but polycystic ovary syndrome was developed. Whole-exome gene sequencing revealed a GCKR gene c. 69delG heterozygous mutation. After molecular diagnosis, the insulin dosage was gradually reduced to full cessation, and only metformin sustained-release tablets were taken to control blood glucose. It is necessary to regular evaluate islet function of patient with type 1 diabetes, and genetic test is of significance for accurate diagnosis and treatment.

Progress in the pathogenesis of primary atopic diseases / 中华实用儿科临床杂志

Atopic diseases used to be considered as complex polygenic diseases with the interaction of environmental factors and genetic susceptibility.In recent years, primary atopic diseases caused by single-gene mutations have been well concerned.This study aims to review the pathogenesis and clinical characteristics of atopic diseases, thus strengthening the understanding.

Prenatal diagnosis of monogenic skeletal disorders in 22 pedigrees / 中华内分泌代谢杂志

Objective:To evaluate the clinical value of prenatal molecular diagnostic technology in preventing hereditary diseases through analysis of prenatal diagnostic characteristics in 22 monogenic skeletal disorders pedigrees.Methods:This study retrospectively analyzed prenatal molecular diagnostic results of 22 pedigrees with monogenic skeletal disorders who were admitted to Department of Osteoporosis and Bone Diseases in our hospital from January 2014 to July 2021.Results:Among 22 pedigrees, there were 10 pedigrees with X-linked hypophosphatemic rickets due to PHEX gene mutations, in which 8 fetuses were found to carry pathogenic variants; 6 pedigrees with osteopetrosis, including 3 cases of CLCN7 gene mutation, 2 TCIRG1 gene mutation, and 1 CTSK gene mutation, were detected to have 2 affected fetuses and 1 carrier. There were 4 cases of osteogenesis imperfecta, including 2 cases of COL1A1 gene mutation, 1 case of COL1A2 gene mutation, and 1 case of SERPINF1 gene mutation, in which 1 affected fetus and 1 carrier were found; only one case of osteoarthritis with mild chondrodysplasia caused by COL2A1 gene mutation was found to harbor pathogenic variant in fetus; 1 case of hypophosphatasia due to ALPL gene mutation was not detected to carry pathogenic variant in fetus. By the time of follow-up, all 12 affected fetuses were terminated, and the remaining 10 fetuses except for one case still in pregnancy were born in good condition.Conclusion:Prenatal molecular diagnosis may confirm whether the fetus carries pathogenic variants at the first and second trimesters. For monogenic skeletal disorders that comply with Mendel′s law of separation, prenatal diagnosis can be determined by calculating the probability of recurrence of offspring. In addition, for families with de novo mutations in the offspring, it is necessary to pay attention to whether there are mosaic mutations in the parents.

Significance of molecular diagnostic technology in the diagnosis and treatment of inflammatory bowel disease in children / 中华实用儿科临床杂志

With the development of biological technology, molecular diagnosis has been increasingly applied in clinical practice and treatment.Inflammatory bowel disease (IBD) in children is a chronic intestinal inflammation caused by infection, immunity, environment and other factors in a specific genetic background.Children with IBD, especially early-onset and very early-onset IBD, can be considered a monogenic disease.Early identification of such children in clinical work and timely improvement of gene detection can identify the types of gene defects and reveal the inflammatory signal transduction pathways, providing a theoretical basis for the selection of treatment options.Moreover, drug-related pharmacogenetics in the treatment of IBD directly affects the organism′s response rate to drugs, thereby affecting the clinical remission and intestinal mucosal repair.Therefore, the understanding of the characteristics of drug immunogenicity of the Asian population, which can reduce the unnecessary waste of medical resources, the adverse drug reactions in children during the induction and maintenance of remission and complications and recurrence rate, is of great importance.

Rare Variants of Monogenic Cerebral Small Vessel Diseases -Related Genes: A Study in a Cohort of Patients with Cerebral Small Vessel Diseases / 罕见病研究

  Objective  This study aimed at describing the frequency of rare variants of monogenic cerebral small vessel diseases (CSVD) in a cohort of patients with CSVD, and to explore its clinical relevance.  Methods  This study included CSVD patients visiting the Neurology Department of Peking Union Medical College Hospital(PUMCH) from March 2017 to January 2022, collecting their demographic and clinical information and DNA samples for whole-exome sequencing. Descriptive analysis and statistical analysis were conducted exploring the differences between monogenic CSVD-related gene mutation carriers and noncarriers.  Results  A total of 292 patients were included, 51.03% of whom carried one or more rare variants of monogenic CSVD-related genes. The most common rare low-frequency variants were located in the NOTCH3 gene (70 patients, 23.97%), followed by HTRA1 and COL4A1/COL4A2 (22 patients, 7.53%) respectively. Among the subgroup of patients without a family history of stroke (n=176), the frequency of rare variants was as high as 47.16%. Compared with non-carriers, the carriers were diagnosed at a younger age (58.76±13.71 vs. 63.46±13.21, P=0.003). No difference was found in phenotypes among single-SNP carriers, multiple-SNPs carriers, and noncarriers.  Conclusions  The frequency of rare mutation of monogenic CSVD-related genes were relatively high in Chinese CSVD cohort. The most common rare variant was within the NOTCH3, followed by HTRA1 and COL4A1/COL4A2 genes. For CSVD patients of unknown causes, genetic screening should not be neglected even if there is not a family history of the disease.

Advances of monogenic kidney stone diseases associated with purine metabolism / 中华泌尿外科杂志

Some kidney stones are caused by single gene mutations, and monogenic kidney stone diseases associated with purine metabolic disorder mainly including adenine phosphoribosyltransferase(APRT) deficiency, hypoxanthine-guanine phosphoribosyltransferase(HPRT)deficiency, hereditary xanthinuria(HX), and some diseases caused by gene mutations such as PRS1, SLC22A12, SLC2A9 and ABCG2. Such diseases can lead to abnormal metabolism of purine and uric acid, and then form 2, 8-dihydroxyadenine stones, uric acid stones or xanthine stones. This kind of diseases are rare, the genotype and phenotype of different types of monogenic diseases related to purine metabolism have their own characteristics and are not widely recognized. At present, the main treatment is medical therapy. Gene sequencing will make the diagnosis and find more disease-related genes or mutations. Gene editing, such as CRISPR/Cas9 technology, makes it possible to cure monogenic kidney stone diseases associated with purine metabolism disorder in the future.

Clinical progress of monogenic autoimmune syndrome associated with type 1 diabetes mellitus / 中国医师杂志

The impairment of islets β cell by autoimmune response is an important cause of type 1 diabetes mellitus (T1DM). Some monogenic autoimmune syndromes could induce T1DM in difference chance, which are important disease models to deeply understand autoimmunity and T1DM. This article reviews the diagnosis, treatment and genetic detection of eight known single gene autoimmune syndromes associated with T1DM, arming to expand the diagnosis and treatment of T1DM.

MODY probability calculator for GCK and HNF1A screening in a multiethnic background population

ABSTRACT Objective We aimed to identify the frequency of monogenic diabetes, which is poorly studied in multiethnic populations, due to GCK or HNF1A mutations in patients with suggestive clinical characteristics from the Brazilian population, as well as investigate if the MODY probability calculator (MPC) could help patients with their selection. Subjects and methods Inclusion criteria were patients with DM diagnosed before 35 years; body mass index < 30 kg/m2; negative autoantibodies; and family history of DM in two or more generations. We sequenced HNF1A in 27 patients and GCK in seven subjects with asymptomatic mild fasting hyperglycemia. In addition, we calculated MODY probability with MPC. Results We identified 11 mutations in 34 patients (32.3%). We found three novel mutations. In the GCK group, six cases had mutations (85.7%), and their MODY probability on MPC was higher than 50%. In the HNF1A group, five of 27 individuals had mutations (18.5%). The MPC was higher than 75% in 11 subjects (including all five cases with HNF1A mutations). Conclusion Approximately one third of the studied patients have GCK or HNF1A mutations. Inclusion criteria included efficiency in detecting patients with GCK mutations but not for HNF1A mutations (< 20%). MPC was helpful in narrowing the number of candidates for HNF1A screening.

Síndrome nefrótico congénito. Reporte de caso y revisión del enfoque diagnóstico / Congenital nephrotic syndrome. Case report and review of its diagnostic work up

Resumen El síndrome nefrótico se define como la unión de proteinuria masiva, hipoalbuminemia e hiperlipidemia, que pueden asociarse a edemas e hipercoagulabilidad. Se origina de una anormalidad de la barrera de filtración glomerular con una fuga masiva de proteína y los efectos secundarios consecuentes. En sus formas primarias, ocurre con una incidencia de 1-3 por cada 100.000 niños menores de 16 años. La forma congénita es una variante poco frecuente del síndrome nefrótico, la cual se presenta en el nacimiento o dentro de los tres primeros meses de vida, y suele ser resistente a la corticoterapia. Se debe evaluar primero la existencia de infecciones congénitas y luego buscar las enfermedades monogénicas más comunes, finalmente se puede recurrir a la secuenciación de nueva generación para buscar mutaciones en los demás genes candidatos. Se presenta el caso de una niña con síndrome nefrótico congénito de difícil control, enfatizando en el proceso diagnóstico y el manejo de soporte. Se resalta la importancia de la asesoría genética a la familia en todos los casos.

Abstract A nephrotic syndrome is defined as the association of massive proteinuria, hypoalbuminemia and hyperlipidemia, which may be associated with edema and hypercoagulability. It originates from an abnormality of the glomerular filtration barrier with a massive protein leak and the consequent side effects. In its primary forms, it occurs with an incidence of 1 - 3 per 100,000 children under 16 years of age. The congenital form is a rare variant of the nephrotic syndrome, which occurs at birth or within the first three months of life and is usually resistant to corticosteroid therapy. Congenital infections and most common related monogenic diseases should be tested. Finally, new generation sequencing must be used to search for mutations in other candidate genes. We present the case of a girl with congenital nephrotic syndrome difficult to control, emphasizing the diagnostic process and support management. The importance of genetic counseling to the family in all cases is highlighted.

Searching for mutations in the HNF1B gene in a Brazilian cohort with renal cysts and hyperglycemia

ABSTRACT Objective To verify the presence of variants in HNF1B in a sample of the Brazilian population selected according to the presence of renal cysts associated with hyperglycemia. Subjects and methods We evaluated 28 unrelated patients with clinical suspicion of HNF1B mutation because of the concomitant presence of diabetes mellitus (DM) or prediabetes and renal cysts. Genotyping was accomplished using Sanger sequencing or multiplex ligation-dependent probe amplification (MLPA). In positive cases, available relatives were recruited. Results We found two patients with HNF1B mutations. The first presented the variant p.Pro328Leufs*48(c.983delC) and had DM, renal cysts, and hypomagnesemia. The second presented a heterozygous whole gene deletion in HNF1B, DM, renal cysts, body and tail pancreatic agenesis, and hypomagnesemia; this alteration was also found in his two siblings and his father. Conclusion The recruitment of suspected cases of HNF1B gene mutations in Brazilians due to hyperglycemia and renal cysts presents two positive cases. Our cases contribute to the annotation of clinical and biochemical phenotypes of this rare form of maturity-onset diabetes of the young (MODY).

Clinical features and precision medicine of the six most common types of monogenic diabetes / 中华内分泌代谢杂志

Monogenic diabetes is a special type of diabetes caused by a single gene mutation, and it is commonly misdiagnosed in clinical practice. The two major forms of monogenic diabetes are neonatal diabetes(NDM) and maturity onset diabetes of the young(MODY). The most common mutations in 6 genes, induding HNF1α, GCK, HNF4α, KCNJ11, ABCC8, and INS, account for more than 90% of all monogenic diabetic cases. This article is to review recent advances in clinical features, and precision medicine of monogenic diabetes, and to discuss the significance of insights gained from monogenic diabetes in better understanding the pathogenesis of type 1 and type 2 diabetes. The current models for screening of monogenic diabetes were also discussed.

Analysis of extreme obesity in two pedigrees due to leptin receptor mutation / 中华内分泌代谢杂志

This study reported two women with extreme obesity who underwent metabolic surgery due to their mutations in leptin receptor (LEPR).Genomic DNA was extracted from the anticoagulant blood samples of the two patients and their parents.A panel of genes related to metabolic diseases or whole exon sequencing was screened and the results were confirmed by Sanger sequencing.This is the first time that these three mutations in LEPR were reported.Two patients complained insatiety and early-onset obesity since childhood at clinics.Patient 1 was a 39-year-old woman with height 150 cm,weight 130 kg,and BMI 57.8 kg/m2.Serum leptin level was 156.4 μg/L.A homozygous mutation of c.2317G＞T was found in exon 15 of LEPR gene in patient 1,which was descended from her father and mother respectively.Patient 2 was a 37-year-old woman with height 158 cm,weight 167 kg,and BMI 67 kg/m2.Serum leptin level was 193.4 μg/L.Genetic analysis showed compound heterozygous mutations of c.1482delT and c.1892C ＞ A.Her father showed heterozygous c.1482delT mutation,and her mother carried heterozygous c.1892C ＞ A mutation.Two patients all underwent metabolic surgery with body weight reduction of about 22 kg and 40 kg respectively after first six months.However,the follow-up studies showed that the body weight of patient 1 rebounded to pre-surgery level in two years and patient 2 did not further lose weight in the following six months.

Congenital diarrhea and enteropathies in children / 中国实用儿科杂志

Congenital diarrhea and enteropathies(CODEs)are typically monogenic disorders. Patients always present with persistent and severe chronic diarrhea. The diagnosis of CODEs is oftern delayed and there is a high mortality. Application of endoscopy,histologic evaluation and next generation sequencing might facilitate the diagnosis,and precision medicine to patients with CODEs.

Clinical application of SNP haplotype analysis in the preimplantation genetic diagnosis (PGD) of monogenic diseases / 临床检验杂志

Objective@#To investigate the clinical application value of single nucleotide polymorphism (SNP) haplotype analysis in the preimplantation genetic diagnosis (PGD) of monogenic diseases. @*Methods@#The whole genome amplification products of biopsied trophectoderm cells were analyzed by SNP haplotype analysis and verified by Sanger sequencing. @*Results@#A total of 205 embryos were performed SNP haplotype analysis and Sanger sequencing. Among them, Sanger sequencing failed in 14.63% (30/205) of embryos, and SNP haplotype analysis failed in 0.98% (2/205) of embryos. The failure rate of the latter was significantly lower than that of the former (P＜0.05). There were consistent results in 155 (75.61%) embryos, and inconsistent results in 18 (8.78%) embryos. Forty-five embryos in 41 cycles were performed embryo transplantation. The clinical pregnancy rate was 70.73% (29/41) and the implantation rate was 71.11% (32/45). The results of prenatal diagnosis of amniotic fluid during the second trimester of pregnancy were completely consistent with those of SNP haplotype analysis. @*Conclusion@#SNP haplotype analysis is accurate, and its failure rate is lower than that of Sanger sequencing. It can be effectively used in the PGD of clinical monogenic diseases.

Obesidad monogénica / Monogenic obesity

La obesidad infantil es un problema creciente de salud, asociado con una significativa morbilidad física y psicológica a edades tempranas. La obesidad es una enfermedad multifactorial, causada en la mayoría de los casos por la interacción de determinados polimorfismos genéticos con el medio ambiente. Solo en un 5 % resulta de mutaciones en genes específicos, originando en algunos casos síndromes mendelianos de muy escasa incidencia en la población que se clasifican como obesidades monogenicas. La mayoría de estos genes están implicados en la regulación del hambre-saciedad en el sistema nervioso central, en el cual el eje de leptina-melanocortina desempeña un rol fundamental. Se presentan clínicamente como formas de obesidad de inicio precoz, severas, que se asocian con trastornos de la conducta alimentaria y alteraciones endocrinológicas. La mutación en el gen del receptor melanocortina-4 (MC4R) es la causa más común de obesidad monogénica grave de aparición temprana. El objetivo de esta revisión es realizar una actualización sobre las obesidades de inicio precoz de causa monogénicas, su etiopatogenia, sus principales características clínicas y su abordaje terapéutico. El manejo de estos pacientes aún es un reto, ya que el tratamiento específico solo se encuentra disponible en un solo tipo de obesidad monogénica. Para el resto de los tipos se encuentran en investigación nuevas moléculas que actúan sobre la vía leptina-melanocortina

Childhood obesity is a growing health problem associated with significant physical and psychological morbidity at an early age. Obesity is a multifactorial disease in the majority of cases caused by an interaction of certain genetic polymorphisms and the environment. In only 5% of the patients it is related to specific gene mutations in some cases resulting in very rare Mendelian syndromes classified as monogenic obesity. The majority of these genes are involved in the hunger-satiety regulation in the central nervous system, in which the leptin-melanocortin axis plays a fundamental role. Clinically, these forms of obesity present at an early age, are severe, and are associated with eating disorders and endocrine alterations. A mutation in the melanocortine-4 receptor (MC4R) gene is the most common cause of early-onset severe monogenic obesity. The aim of this review was to provide an update of the different forms of early-onset monogenic obesity, focusing on the etiopathogenicity, main clinical features, and therapeutic approach. The management of these patients is still a challenge as specific treatment is only available for one type of monogenic obesity. For the remaining types new molecules that act on the leptin-melanocortin pathway are currently being investigated

Application of next-generation sequencing in monogenic diabetes / 中国糖尿病杂志

[Summary] Next-generation sequencing is a revolution in the approach of genetic testing. It broadens the insight on the genetic diagnosis and research of monogenetic diabetes,which is represented by neonatal diabetes mellitus and maturity onset diabetes of the young.And it reveals advantages in exploring novel mutations.

Challenges and opportunities of drug research and development in rare diseases / 国际药学研究杂志

Rare diseases, although individually rare, affect approximately 6%-8% of the total population with more than 6000 diseases identified. The significance of and unmet need in rare diseases for both patients and society are high. Development of new treatments for rare diseases is associated with significant challenges such as low market potential for innovative pharmaceutical companies, often unclear regulatory path, lack of validated clinical endpoints and patient reported outcomes and insufficient data regarding the disease. Special incentivizing strategies such as market exclusivity, waiver or reduction of regulatory submission fees and assistance in clinical trial protocol development and tax incentives have been implemented to enhance drug development in rare and neglected diseases. The ultimate goal of these strategies is to help patients receive adequate treatments irrespective of the epidemiology of their disease. Furthermore, rare diseases, often with a well-defined pathogenesis, represent a unique opportunity for drug discovery in a given homogeneous disease with subsequent indication expansions. Although the number of rare disease treatments that became available for patients has increased, the unmet medical need is still high in this special population.

Síndrome de Meckel - Gruber recurrente / Recurrent Meckel - Gruber syndrome

Se describe el caso clínico de una adolescente de 18 años de edad, con 20,1 semanas de gestación, quien fue remitida por primera vez en 2009 al Centro Provincial de Genética, fecha en la que ya estaba casada con su pareja actual. A partir de ahí se sucedieron una serie de eventos obstétricos desfavorables y, finalmente, teniendo en cuenta los hallazgos ecográficos y la recurrencia de estos en la misma paciente se comprobó que ella y su esposo eran portadores de la mutación que produce el síndrome de Meckel - Gruber.

Abstract The case report of an 18 years adolescent with 20.1 weeks of gravidity is described who was referred for the first time in 2009 to the Genetics Provincial Center, when she was already married with her current couple. Since that time on, a series of unfavorable obstetric events appeared and, finally, taking into account the echographic findings and its recurrence in the same patient, it was proven that she and her husband were carriers of the mutation that produces the Meckel - Gruber syndrome.