Primordial dwarfism (PD) refers to a group of monogenic genetic disorders characterized by intrauterine growth restriction (IUGR) and severe, persistent postnatal growth retardation. These diseases have been associated with variants of multiple genes whose products are mainly involved in critical cellular biological processes such as maintenance of genomic stability, DNA damage repair, mRNA splicing regulation, and centrosome function. Variants of such genes can directly impair cell proliferation and developmental potential. With the widespread application of molecular genetic technologies such as high-throughput sequencing, significant progress has been made in the research of PD. This article focuses on the major subtypes of PD, including Seckel syndrome, Microcephalic osteodysplastic primordial dwarfism (MOPD) types I/III, MOPD type II, and Meier-Gorlin syndrome. It has systematically summarized the advances in their clinical phenotypic characteristics, pathogenic genes, and molecular mechanisms, with an aim to deepen the understanding of the essence of growth disorders associated with PD.
Humans ; Dwarfism/genetics* ; Microcephaly/genetics* ; Phenotype ; Fetal Growth Retardation/genetics* ; Osteochondrodysplasias/genetics* ; Growth Disorders ; Micrognathism ; Patella/abnormalities* ; Congenital Microtia

Patient 1, a 3-year-6-month-old male, presented with feeding difficulties and delayed motor development. He exhibited poor responsiveness at birth, weak crying, intellectual and motor delays, low immunity, recurrent respiratory infections, hypotonia of the limbs, and distinctive facial features (low-set ears, double chin, and high arched palate), as well as a single transverse palmar crease on the right hand. Genetic testing revealed a c.1096C>T heterozygous variant in the SMARCB1 gene. Patient 2, a 3-year-old male, presented with developmental delay and distinctive facial features. Genetic testing identified the same pathogenic mutation as in Patient 1. The two patients are unrelated, and clinical phenotyping and genetic testing confirmed both cases as Coffin-Siris syndrome type 3. Coffin-Siris syndrome is a rare genetic disorder, and early genetic testing can aid in diagnosis.
Child, Preschool ; Humans ; Male ; Abnormalities, Multiple/genetics* ; Chromosomal Proteins, Non-Histone/genetics* ; Ear/abnormalities* ; Face/abnormalities* ; Hand Deformities, Congenital/genetics* ; Intellectual Disability/genetics* ; Micrognathism/genetics* ; Mutation ; Neck/abnormalities*

OBJECTIVES: To study genotype-phenotype correlations in children with FGFR3 variants and to improve clinical recognition of related disorders. METHODS: Clinical data of 95 patients aged 0-18 years harboring FGFR3 variants, confirmed by whole‑exome sequencing at Shanghai Children's Medical Center from January 2012 to December 2023, were retrospectively reviewed. Detailed phenotypic characterization was performed for 22 patients with achondroplasia (ACH) and 10 with hypochondroplasia (HCH). RESULTS: Among the 95 patients, 52 (55%) had ACH, 24 (25%) had HCH, 9 (9%) had thanatophoric dysplasia, 3 (3%) had syndromic skeletal dysplasia, 2 (2%) had severe achondroplasia with developmental delay and acanthosis nigricans, and 5 (5%) remained unclassified. A previously unreported FGFR3 variant, c.1663G>T, was identified. All 22 ACH patients presented with disproportionate short stature accompanied by limb dysplasia, commonly with macrocephaly, a depressed nasal bridge, bowed legs, and frontal bossing; complications were present in 17 (77%). The 10 HCH patients predominantly exhibited disproportionate short stature with limb dysplasia and depressed nasal bridge. CONCLUSIONS ACH is the most frequent phenotype associated with FGFR3 variants, and missense variants constitute the predominant variant type. The degree of FGFR3 activation appears to correlate with the clinical severity of skeletal dysplasia.
Humans ; Receptor, Fibroblast Growth Factor, Type 3/genetics* ; Child ; Male ; Child, Preschool ; Female ; Infant ; Adolescent ; Dwarfism/genetics* ; Achondroplasia/genetics* ; Lordosis/genetics* ; Infant, Newborn ; Retrospective Studies ; Genetic Association Studies ; Bone and Bones/abnormalities* ; Phenotype ; Limb Deformities, Congenital

OBJECTIVE: To explore the clinical features, genetic characteristics in a child with Miller-McKusick-Malvaux syndrome (3MS) type 1 caused by CUL7 gene variant. METHODS: A child diagnosed with 3MS type 1 at the Children's Hospital Affiliated to Zhengzhou University in February 2021 was selected as the subject of this study. Peripheral blood samples were collected from the child and her parents for genomic DNA extraction. Whole exome sequencing (WES) was performed on the child, and Sanger sequencing was used to validate the candidate variants and analyze their pathogenicity. A literature search was conducted using the keywords "3M syndrome" in the China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, and PubMed databases from inception to December 2024. The clinical data of Chinese children with 3MS reported in the literature were summarized. This study was approved by the Medical Ethics Committee of the Children's Hospital Affiliated to Zhengzhou University (Ethics No. 2024-K-020). RESULTS: The child was a 6-year-old and 2-month-old female with facial dysmorphism, skeletal abnormalities, and growth and developmental delay. WES revealed compound heterozygous variants in the CUL7 gene: c.2686G>T (p.E896*) and c.1200delT (p.R401Gfs66). Sanger sequencing confirmed that these two variants were inherited from the child's father and mother, respectively. According to the American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines for the Interpretation of Sequence Variants, c.2686G>T (p.E896) was classified as a pathogenic (PVS1+PM2_Supporting+PM3), and c.1200delT (p.R401Gfs*66) was classified as a likely pathogenic (PVS1+PM2_Supporting). Based on the literature search strategy, 18 relevant articles were identified, including a total of 32 Chinese cases of 3MS, of which 8 were fetuses. A total of 32 Chinese 3MS cases were included in the literature review, of which 8 were fetuses. The majority of these cases carried variants in the CUL7 gene (20/32, 62.5%) and OBSL1 gene (12/32, 37.5%). The main clinical manifestations included intrauterine or postnatal growth and developmental delay (32/32, 100.0%), triangular facies (27/32, 84.3%), and skeletal abnormalities (21/32, 65.6%). CONCLUSION The compound heterozygous variants c.2686G>T (p.E896*) and c.1200delT (p.R401Gfs*66) in the CUL7 gene are likely the genetic cause of 3MS type 1 in the child. For children presenting with facial dysmorphism, skeletal abnormalities, and intrauterine or postnatal growth and developmental delay, 3MS should be considered as a differential diagnosis.
Humans ; Cullin Proteins/genetics* ; Female ; Child ; Limb Deformities, Congenital/genetics* ; Exome Sequencing ; Mutation ; Child, Preschool ; Dwarfism ; Muscle Hypotonia ; Spine/abnormalities*

OBJECTIVE: To explore the genetic characteristics of a fetus affected with Structural heart defects and renal anomalies syndrome (SHDRA). METHODS: A pedigree with SHDRA (fetus and the parents) who had visited the Affiliated Women and Children's Hospital of Ningbo University in April 2023 was selected as the study subject. Clinical data of the family were collected. A total of 10 mL of amniotic fluid cells from the fetus and 5 mL of peripheral blood samples from the parents were collected for genomic DNA extraction. Trio whole-exome sequencing (Trio-WES) was performed, and Sanger sequencing was used to validate candidate variants in the family. The identified variants were classified according to the Standards and Guidelines for the Interpretation of Sequence Variants established by the American College of Medical Genetics and Genomics (ACMG) (hereinafter referred to as the "ACMG Guidelines). Relevant research literature on SHDRA in domestic and international databases were searched for literature review. This study was approved by the Affiliated Women and Children's Hospital of Ningbo University (Ethics No. EC2023-094). RESULTS: In this family, prenatal ultrasound at 18 weeks of gestation revealed left renal multicystic dysplasia in the fetus. After birth, the infant exhibited an ostium secundum atrial septal defect, patent ductus arteriosus, and left renal multicystic dysplasia. Trio-WES revealed that the fetus had carried c.344dup (p.L116Afs*32) and c.90_104dup (p.Ala31_Ala35dup) compound heterozygous variants in the TMEM260 gene, which were respectively inherited from its father and mother. According to the ACMG guidelines, the c.344dup (p.L116Afs*32) and c.90_104dup (p.Ala31_Ala35dup) variants were classified as pathogenic (PM2_Supporting+PVS1+PP4) and likely pathogenic (PM2_Supporting+PM4+PM3+PP4), respectively. According to the literature search strategy set for this study, a total of 6 literature was retrieved, involving 25 SHDRA patients from 20 families. Together with the patients in this study, there were 14 TMEM260 gene variants, most of which were frameshift variants (7 types) and had located in exons 3, 11 and 13. The main clinical features of SHDRA were congenital heart malformation, renal abnormality and neurodevelopmental abnormality, and there was a lack of genotype-phenotype correlation. CONCLUSION The c.344dup (p.L116Afs*32) and c.90_104dup (p.Ala31_Ala35dup) variants of the TMEM260 gene probably underlay the SHDRA in this family. Above finding has provided a basis for clinical diagnosis and genetic counseling for the family.
Humans ; Female ; Pedigree ; Membrane Proteins/genetics* ; Male ; Heart Defects, Congenital/genetics* ; Kidney/abnormalities* ; Pregnancy ; Adult ; Kidney Diseases/congenital* ; Exome Sequencing ; Mutation ; Genetic Testing

OBJECTIVE: To assess the diagnostic value of whole exome sequencing (WES) for fetuses undergone induced abortion due to structural abnormalities. METHODS: A retrospective analysis was carried out on 43 aborted fetuses with negative results for copy number variation (CNV) testing from January 2023 to June 2024 at Northwest Women's and Children's Hospital. Trio-WES was carried out on the tissues from the aborted fetuses. This study has been approved by the Ethics Committee of the Hospital (Ethics No. 21-036). RESULTS: Among the 43 abortic fetuses, WES has detected pathogenic variants in 15 cases, with a total of 9 pathogenic variants, 5 suspected pathogenic variants, and 5 variants of uncertain significance. No definite pathogenic variants were detected in the remaining 28 cases. CONCLUSION For fetuses with structural abnormalities and negative results from CNV testing, WES can increase the diagnostic rate and facilitate etiological diagnosis and genetic counseling.
Humans ; Female ; Exome Sequencing/methods* ; Pregnancy ; DNA Copy Number Variations/genetics* ; Retrospective Studies ; Adult ; Prenatal Diagnosis/methods* ; Abortion, Induced ; Fetus/abnormalities* ; Congenital Abnormalities/diagnosis* ; Genetic Testing ; Aborted Fetus/abnormalities*

OBJECTIVE: To explore the genetic etiology of a Chinese boy affected with Oculo-facio-cardio-dental syndrome (OFCD). METHODS: A child diagnosed with OFCD at West China Hospital of Sichuan University on September 21, 2024 was selected as the study subject. Clinical phenotype of the child was collected through ophthalmologic examination, cardiac ultrasonography, and X-ray imaging. Potential pathogenic variants were detected by trio-whole exome sequencing (Trio-WES). Candidate variant was validated with TA-cloning followed by Sanger sequencing. Mosaic variant was analyzed by ultra-deep sequencing (10,000-fold) and quantitative PCR. This study was approved by the Medical Ethics Committee of the West China Hospital of Sichuan University (Ethics No.: 2019-772 ). RESULTS: The proband had presented with congenital cataracts, mitosis, atrial and ventricular septal defects, dental abnormalities, and right radioulnar synostosis. His mother also exhibited congenital cataracts and dental anomalies, suggesting a diagnosis of OFCD. Trio-WES revealed an novel heterozygous 14-bp deletion (c.4724_4737del) in exon 12 of the BCOR gene in the proband. Deep sequencing identified a mosaic BCOR c.4724_4737del mutation in approximately 3.4% of peripheral leukocytes from his mother. Quantitative PCR analysis also confirmed the presence of this low-level mosaicism. The 14-bp deletion was predicted to cause a frame shift and premature termination (p.Met1575AsnfsTer6). Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PVS1+PM2+PP1). CONCLUSION Above findings have expanded the spectrum of BCOR mutations associated with OFCD, which highlighted the role of low-level mosaicism with maternal transmission and provided a basis for genetic counseling and reproductive guidance for the family.
Humans ; Male ; Repressor Proteins/genetics* ; Proto-Oncogene Proteins/genetics* ; Tooth Abnormalities/genetics* ; Eye Abnormalities/genetics* ; Microphthalmos/genetics* ; Child ; Sequence Deletion ; Female ; Cataract/congenital* ; Heart Septal Defects

UNLABELLED: OBJECTIVE：To explore the clinical characteristics and genetic etiology of a child with CAKUTHED syndrome. METHODS: A child who was admitted to the neonatal department of Gansu Provincial Maternal and Child Health Care Hospital due to "neonatal asphyxia" in May 2021 was selected as the study subject. Genomic DNA was extracted from peripheral venous blood samples from the child and his parents, and whole exome sequencing (WES) was carried out. Sanger sequencing was used to verify the candidate variant of the PBX1 gene. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the pathogenicity of candidate variants was rated. This study was approved by the Medical Ethics Committee of the Hospital [Ethics No.: 2021GSFY (65)]. RESULTS: The proband, a male neonate, manifested renal dysplasia, congenital heart disease, pulmonary dysplasia, mediastinal hernia, cryptorchidism, and clavicle dysplasia. WES revealed that he had harbored a heterozygous c.863G>A (p.Arg288Gln) missense variant in exon 6 of PBX1 gene, which resulted substitution of Arginine at position 288 by Glutamine, for which both parents were of the wild type. The variant was unreported previously and rated as pathogenic (PS2+PM1+PM2_Supporting+PP2+PP3) based on the ACMG guidelines. CONCLUSION The c.863G>A variant of the PBX1 gene probably underlay the pathogenesis in the proband. Above finding has enriched the mutational spectrum of the PBX1 gene.
Humans ; Male ; Pre-B-Cell Leukemia Transcription Factor 1/genetics* ; Phenotype ; Infant, Newborn ; Exome Sequencing ; Mutation, Missense ; Heart Defects, Congenital/genetics* ; Abnormalities, Multiple/genetics*

OBJECTIVE: To explore the genetic basis for a fetus with Cardiac-urogenital syndrome (CUGS). METHODS: A fetus with congenital heart disease identified at the Maternal Fetal Medical Center for Fetal Heart Disease, Beijing Anzhen Hospital Affiliated to Capital Medical University in January 2019 was selected as the study subject. Clinical data of the fetus was collected. Copy number variation sequencing (CNV-seq) and trio-whole exome sequencing (trio-WES) were carried out for the fetus and its parents. Candidate variants were verified by Sanger sequencing. RESULTS: Detailed fetal echocardiographic examination had revealed hypoplastic aortic arch. The results of trio-WES revealed that the fetus has harbored a de novo splice variant of the MYRF gene (c.1792-2A>C), for which both parents were of the wild-type. Sanger sequencing confirmed the variant to be de novo. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as likely pathogenic. CNV-seq has identified no chromosomal anomalies. And the fetus was diagnosed with Cardiac-urogenital syndrome. CONCLUSION The de novo splice variant of the MYRF gene probably underlay the abnormal phenotype in the fetus. Above finding has enriched the spectrum of MYRF gene variants.
Female ; Humans ; DNA Copy Number Variations ; Fetal Diseases ; Fetus/abnormalities* ; Heart Defects, Congenital/genetics* ; Mutation ; Transcription Factors/genetics*

A full-term female infant was admitted at 5 hours after birth due to heart malformations found during the fetal period and cyanosis once after birth. Mmultiple malformations of eyes, face, limbs, and heart were noted. The whole-exome sequencing revealed a pathogenic heterozygous mutation, c.2428C>T(p.Arg810^*), in the BCOR gene. The infant was then diagnosed with oculo-facio-cardio-dental syndrome. He received assisted ventilation to improve oxygenation and nutritional support during hospitalization. Right ventricular double outlet correction was performed 1 month after birth. Ocular lesions were followed up and scheduled for elective surgery. The possibility of oculo-facio-cardio-dental syndrome should be considered for neonates with multiple malformations of eyes, face, and heart, and genetic testing should be performed as early as possible to confirm the diagnosis; meanwhile, active ophthalmic and cardiovascular symptomatic treatment should be given to improve the prognosis.
Female ; Humans ; Infant ; Infant, Newborn ; Male ; Abnormalities, Multiple/therapy* ; Cataract/genetics* ; Cyanosis ; Proto-Oncogene Proteins ; Repressor Proteins/genetics* ; Heart Defects, Congenital/genetics*