Posterior fossa malformations are rare cyst-like pathologies of the central nervous system. Outcomes of patients with these conditions are largely documented in fetal or early childhood studies as most cases are non-compatible with life. Also, different schemes to categorize these occurrences have been proposed. One classification puts forth that the entities are a continuum of pathologies, called the Dandy Walker Complex, wherein Mega Cisterna Magna is the most benign to Dandy Walker Malformation as the most severe form. We report the first case of a patient with a mixed presentation of Mega Cisterna Magna having extracranial manifestations of Dandy Walker Malformation reaching her adult years. The patient is a 26-year-old female who was apparently well until she presented with recurrent headache and seizure episodes of 2-year duration. She had an unremarkable birth and childhood history, apart from learning difficulties in school. In her adult years, she gave birth to an infant with multiple physical anomalies. She has a maternal uncle with abnormal facie and intellectual disability. Physical examination of the patient exhibited a bulging occiput, hypertelorism, down-slanting palpebral fissures, large globular nose, large ear lobules, high arched palate, and clinodactyly. Neurologic examination was unremarkable. Magnetic resonance imaging confirmed Mega Cisterna Magna and was deemed non-surgical. She remained seizure-free during admission as well as on followup, maintained on Phenytoin. The existence of a Dandy-Walker continuum is still debated, as the link among the disease entities are yet to be established using developmental or genetic studies. This case, however, supports the Dandy-Walker Complex classification by demonstrating a rare combination of Mega Cisterna Magna with features of Dandy-Walker Malformation in an adult. This can contribute to disease definition and eventually to the discovery of the pathobiological mechanisms of posterior fossa cysts, and to appropriate diagnosis and management.

The patient is a male neonate born at term. He was admitted 16 minutes after birth due to stridor and inspiratory respiratory distress. Physical examination revealed a cleft palate, and a grade II systolic ejection murmur was audible at the left sternal border. Whole exome sequencing identified a heterozygous variant in the SON gene, c.5753-5756del (p.Val1918GlufsTer87), which was absent in either parent, indicating a de novo mutation. According to the guidelines of the American College of Medical Genetics and Genomics, this was classified as a "pathogenic variant" leading to a diagnosis of Zhu-Tokita-Takenouchi-Kim (ZTTK) syndrome. Upon admission, symptomatic supportive treatment was provided. Follow-up at the age of 8 months revealed persistent stridor; the infant could only consume small amounts of milk and was unable to sit steadily. This patient represents the youngest reported case to date, and his symptoms expand the clinical spectrum of the disease, providing valuable insights for clinical diagnosis and treatment.
Humans ; Infant, Newborn ; Male ; Minor Histocompatibility Antigens/genetics* ; DNA-Binding Proteins/genetics* ; Rare Diseases/genetics* ; Neurodevelopmental Disorders/genetics*

Posterior fossa malformations are rare cyst-like pathologies of the central nervous system. Outcomes of patients with these conditions are largely documented in fetal or early childhood studies as most cases are non-compatible with life. Also, different schemes to categorize these occurrences have been proposed. One classification puts forth that the entities are a continuum of pathologies, called the Dandy Walker Complex, wherein Mega Cisterna Magna is the most benign to Dandy Walker Malformation as the most severe form. We report the first case of a patient with a mixed presentation of Mega Cisterna Magna having extracranial manifestations of Dandy Walker Malformation reaching her adult years. The patient is a 26-year-old female who was apparently well until she presented with recurrent headache and seizure episodes of 2-year duration. She had an unremarkable birth and childhood history, apart from learning difficulties in school. In her adult years, she gave birth to an infant with multiple physical anomalies. She has a maternal uncle with abnormal facie and intellectual disability. Physical examination of the patient exhibited a bulging occiput, hypertelorism, down-slanting palpebral fissures, large globular nose, large ear lobules, high arched palate, and clinodactyly. Neurologic examination was unremarkable. Magnetic resonance imaging confirmed Mega Cisterna Magna and was deemed non-surgical. She remained seizure-free during admission as well as on followup, maintained on Phenytoin. The existence of a Dandy-Walker continuum is still debated, as the link among the disease entities are yet to be established using developmental or genetic studies. This case, however, supports the Dandy-Walker Complex classification by demonstrating a rare combination of Mega Cisterna Magna with features of Dandy-Walker Malformation in an adult. This can contribute to disease definition and eventually to the discovery of the pathobiological mechanisms of posterior fossa cysts, and to appropriate diagnosis and management.

OBJECTIVE: To explore the clinical and genetic characteristics of two children diagnosed with two rare genetic diseases simultaneously. METHODS: Two children with comorbidity of two genetic diseases due to dual genetic mutations diagnosed at the Third Affiliated Hospital of Zhengzhou University respectively in May 2022 and March 2023 were selected as the study subjects. Clinical and genetic data of the two children were retrospectively analyzed. This study has been approved by the Ethics Committee of the Third Affiliated Hospital of Zhengzhou University (Ethic No. 2021-062-01). RESULTS: Child 1 was a 2-year-and-4-month-old boy whose clinical manifestations included facial dysmorphism, developmental delay, short stature, microcephaly, cleft palate, cryptorchidism, hypospadias, recurrent infections and immunological abnormalities. Whole exome sequencing revealed that he had harbored a heterozygous c.6595delT (p.Y2199Ifs*65) variant of the KMT2D gene and a heterozygous c.1892G>A (p.R631Q) variant of the PIK3R1 gene. This has led to a dual genetic diagnosis of Kabuki syndrome and PI3Kδ-related immunodeficiency type 36. Child 2 was a 15-year-old girl whose clinical manifestations included epilepsy, Albright's hereditary osteodystrophy, long body trunk, short limbs, hypocalcemia, hyperphosphatemia and hyperparathyroidism. The child also had a family history of short stature. Whole exome sequencing revealed that she had harbored a heterozygous c.2T>C (p.Met1?) variant of the GNAS gene and deletion of exons 2 to 6 of the SHOX gene. The two variants have led to dual diagnose of pseudohypoparathyroidism and X-linked idiopathic short stature. CONCLUSION When the clinical phenotype of a genetic disease is complex and cannot be fully explained with a single genetic variant, multiple pathogenic variants should be considered, and this may lead to the diagnosis of co-morbid genetic diseases. To adopt or supplement corresponding genetic testing in time and re-analyze the genetic data may facilitate accurate diagnosis of co-morbid genetic diseases.
Child, Preschool ; Female ; Humans ; Male ; Class Ia Phosphatidylinositol 3-Kinase/genetics* ; Comorbidity ; Exome Sequencing ; Mutation ; Rare Diseases/genetics* ; Retrospective Studies ; Adolescent

Humans ; Decision Support Systems, Clinical ; Rare Diseases/therapy*

A boy, aged 16 months, attended the hospital due to head and facial erythema for 15 months and vulva erythema for 10 months with aggravation for 5 days. The boy developed perioral and periocular erythema in the neonatal period and had erythema and papules with desquamation and erosion in the neck, armpit, and trigone of vulva in infancy. Blood gas analysis showed metabolic acidosis; the analysis of amino acid and acylcarnitine profiles for inherited metabolic diseases and the analysis of organic acid in urine suggested multiple carboxylase deficiency; genetic testing showed a homozygous mutation of c.1522C>T(p.R508W) in the HLCS gene. Finally the boy was diagnosed with holocarboxylase synthetase deficiency and achieved a good clinical outcome after oral biotin treatment. This article analyzes the clinical data of a child with holocarboxylase synthetase deficiency and summarizes the etiology, diagnosis, and treatment of this child, so as to provide ideas for clinicians to diagnose this rare disease.
Humans ; Male ; Biotin/therapeutic use* ; Holocarboxylase Synthetase Deficiency/drug therapy* ; Homozygote ; Mutation ; Rare Diseases/drug therapy* ; Infant

Rare diseases in children are characterized by low prevalence, complex pathogenesis, variety, and difficulty in the diagnosis and treatment. With the development of medical services, progress has been made in the diagnosis and treatment of rare diseases. However, due to asymmetric allocation of medical resources at different levels, there are still many shortcomings in the establishment and promotion of the homogenized management system of rare disease diagnosis and treatment. In order to further standardize the homogenized management of rare diseases in children, achieve early and accurate diagnosis and treatment, and improve the quality of life of the children, the Rare Disease Diagnosis and Treatment Center of Tianjin Children's Hospital (Tianjin University Children's Hospital) invited relevant experts in the field to develop recommendations for the management model of homogenized diagnosis and treatment of rare diseases in children from the aspects of information construction, hierarchical diagnosis and treatment, personnel training, scientific popularization, and multi-participation. The recommendations provide reference for the regional homogenization of clinical diagnosis and treatment management system for children with rare diseases.
Humans ; Child ; Rare Diseases/therapy* ; Quality of Life

There are more than 7 000 rare diseases and approximately 475 million individuals with rare diseases globally, with children accounting for two-thirds of this population. Due to a relatively small patient population and limited financial resources allocated for drug research and development in pharmaceutical enterprises, there are still no drugs approved for the treatment of several thousands of these rare diseases. At present, there are no drugs for 95% of the patients with rare diseases, and consequently, the therapeutic drugs for rare diseases have been designated as orphan drugs. In order to guide pharmaceutical enterprises to strengthen the research and development of orphan drugs, various nations have enacted the acts for rare disease drugs, promoted and simplified the patent application process for orphan drugs, and provided scientific recommendations and guidance for the research and development of orphan drugs. Since there is a relatively high incidence rate of rare diseases in children, this article reviews the latest research on pharmacotherapy for children with rare diseases.
Humans ; Child ; Rare Diseases/drug therapy* ; Orphan Drug Production ; Pharmaceutical Preparations

Rare diseases refer to a group of single diseases with low incidence rates, complex pathogeneses, severe disease conditions, and rapid progression. Most rare diseases have a genetic background and may occur in childhood. Paying attention to the rare genetic diseases in children and performing early diagnosis and treatment can effectively delay the course of disease and improve the quality of life of children. Many rare diseases can be diagnosed with the help of various experimental techniques, but the diagnosis of rare diseases is still not widely understood. This article summarizes the laboratory diagnostic techniques currently used for rare genetic diseases in children, so as to provide clues for the diagnosis and treatment of such diseases and help to enhance the theoretical understanding and precise medical treatment of rare genetic diseases in children.
Child ; Humans ; Rare Diseases/therapy* ; Quality of Life

ACGS Best Practice Guidelines for Variant Classification in Rare Disease 2020, a supplementary practical guidelines, is based on the Standards and Guidelines for the Interpretation of Sequence Variations issued by the American Society for Medical Genetics and Genomics (ACMG) and the Association of Molecular Pathology (AMP) in 2015 by the British Medical Genetics Society under the Clinical Genomics Society (ACGS), and has integrated the detailed rules of standards developed by the ClinGen Sequence Variant Interpretation (SVI) Working Group by 2020. The further development of the ACMG/AMP guidelines is currently undertaken by the ClinGen SVI working group in the United States, which focuses on the classification of high penetrance and protein coding variants. ClinGen has established many expert panels on variants for specific diseases which required various evidence thresholds and is currently developing disease/gene specific guidelines. The British Medical Genetics Society has collected and integrated information on the guidelines for sequence variation classification and their extended rules, forming its own "2020 ACGS Best Practice Guidelines for Rare Disease Variation Classification" and is regularly updating it. The author has translated and summarized it for the reference of Chinese Medical Genetics Practitioners.
Humans ; Genetic Testing ; Genetic Variation ; Genome, Human ; Rare Diseases/genetics* ; China