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Genes Jan 2024Advanced paternal age increases the risk of transmitting de novo germline mutations, particularly missense mutations activating the receptor tyrosine kinase (RTK)...
Advanced paternal age increases the risk of transmitting de novo germline mutations, particularly missense mutations activating the receptor tyrosine kinase (RTK) signalling pathway, as exemplified by the mutation, which is linked to achondroplasia (ACH). This risk is attributed to the expansion of spermatogonial stem cells carrying the mutation, forming sub-clonal clusters in the ageing testis, thereby increasing the frequency of mutant sperm and the number of affected offspring from older fathers. While prior studies proposed a correlation between sub-clonal cluster expansion in the testis and elevated mutant sperm production in older donors, limited data exist on the universality of this phenomenon. Our study addresses this gap by examining the testis-expansion patterns, as well as the increases in mutations in sperm for two variants-c.1138G>A (p.G380R) and c.1948A>G (p.K650E)-which are associated with ACH or thanatophoric dysplasia (TDII), respectively. Unlike the ACH mutation, which showed sub-clonal expansion events in an aged testis and a significant increase in mutant sperm with the donor's age, as also reported in other studies, the TDII mutation showed focal mutation pockets in the testis but exhibited reduced transmission into sperm and no significant age-related increase. The mechanism behind this divergence remains unclear, suggesting potential pleiotropic effects of aberrant RTK signalling in the male germline, possibly hindering differentiation requiring meiosis. This study provides further insights into the transmission risks of micro-mosaics associated with advanced paternal age in the male germline.
Topics: Aged; Humans; Male; Achondroplasia; Mutation; Receptor Protein-Tyrosine Kinases; Receptor, Fibroblast Growth Factor, Type 3; Semen; Spermatozoa; Testis; Cellular Senescence
PubMed: 38397181
DOI: 10.3390/genes15020191 -
Annals of Medicine and Surgery (2012) Nov 2023Thanatophoric dysplasia is a rare, fatal, and sporadic form of skeletal dysplasia caused by a mutation in fibroblast growth factor receptor 3 (FGFR3). It is...
INTRODUCTION AND IMPORTANCE
Thanatophoric dysplasia is a rare, fatal, and sporadic form of skeletal dysplasia caused by a mutation in fibroblast growth factor receptor 3 (FGFR3). It is characterized by a conical thorax, platyspondyly (flat vertebral bodies), and macrocephaly. This disorder can be diagnosed antenatally as early as 13 weeks of gestation.
CASE PRESENTATION
The authors reported a case of thanatophoric dysplasia on USG in a 19 year old young consanguineous female in her second trimester of pregnancy. Ultrasound examination showed a clover leaf-shaped skull, a widened anterior fontanel, a coarse and edematous face, a flattened nasal bridge, a short neck, a low set of ears, shortening of both upper and lower limbs with short fingers, bowed thighs and legs, and a relatively narrow thorax.
CLINICAL DISCUSSION
Lung hypoplasia, polyhydramnios, and hydrops in affected individuals lead to a poor prognosis. Hence, timely intervention should be done to avoid a poor prognosis. However, a mix of sonographic, genetic, histological, and autopsy studies are applied to make the most accurate diagnosis.
CONCLUSION
The authors reported this case due to the rarity of this condition and the need for a systematic and multidisciplinary approach.
PubMed: 37915702
DOI: 10.1097/MS9.0000000000001356 -
Diagnostics (Basel, Switzerland) Sep 2023This paper presents a rare case of fetal hydrops detected at just 23 weeks of gestation in a 22-year-old woman's first pregnancy. The fetal ultrasound revealed severe...
This paper presents a rare case of fetal hydrops detected at just 23 weeks of gestation in a 22-year-old woman's first pregnancy. The fetal ultrasound revealed severe skeletal anomalies, craniofacial deformities, and thoracic abnormalities, suggesting a complex and severe skeletal dysplasia, potentially type IA Achondrogenesis-a lethal autosomal recessive condition marked by ossification delay. This case highlights the significance of advanced genetic testing, such as next-generation sequencing (NGS) and whole-genome sequencing (WGS), in diagnosing and understanding skeletal dysplasias. Skeletal dysplasias represent a group of genetic disorders that affect osteogenesis. The prevalence of this condition is 1 in 4000 births. Sadly, 25% of affected infants are stillborn, and around 30% do not survive the neonatal period. There is a wide range of rare skeletal dysplasias, each with its own specific recurrence risk, dysmorphic expression, and implications for neonatal survival and quality of life. When skeletal dysplasia is incidentally discovered during routine ultrasound screening in a pregnancy not known to be at risk of a specific syndrome, a systematic examination of the limbs, head, thorax, and spine is necessary to reach the correct diagnosis. Prenatal diagnosis of skeletal dysplasia is crucial for providing accurate counselling to future parents and facilitating the proper management of affected pregnancies. An accurate diagnosis can be a real challenge due to the wide spectrum of clinical presentations of skeletal dysplasia but advances in imaging technologies and molecular genetics have improved accuracy. Additionally, some of these skeletal dysplasias may present clinical overlap, making it especially difficult to distinguish. After the 11th revision of genetic skeletal disorder nosology, there are 771 entities associated with 552 gene mutations. The most common types of skeletal dysplasia are thanatophoric dysplasia, osteogenesis imperfect, achondroplasia, achondrogenesis, and asphyxiating thoracic dystrophy.
PubMed: 37761271
DOI: 10.3390/diagnostics13182905 -
Frontiers in Genetics 2023Prenatal diagnosis of fetal short long bones (SLBs) was reported to be associated with skeletal dysplasias, chromosomal abnormalities, and genetic syndromes. This study...
Prenatal diagnosis of fetal short long bones (SLBs) was reported to be associated with skeletal dysplasias, chromosomal abnormalities, and genetic syndromes. This study aims to identify the genetic causes for fetal short long bones, and retrospectively evaluate the additional diagnostic yield of exome sequencing (ES) for short long bones following the use of conventional genetic testing. A cohort of ninety-four fetuses with sonographically identified short long bones was analyzed by trio-exome sequencing between January 2016 and June 2021. Fetuses with abnormal results of karyotype or chromosomal microarray analysis were excluded. Variants were interpreted based on ACMG/AMP guidelines. All diagnostic variants were validated by Sanger sequencing. Of the 94 fetuses, 38 (40.4%) were found to carry causal genetic variants (pathogenic or likely pathogenic) in sixteen genes with 38 variants. Five fetuses (5.3%) had variant(s) of uncertain significance. Thirty-five cases (37.2%) were diagnosed as genetic skeletal dysplasias including 14 different diseases that were classified into 10 groups according to the Nosology and Classification of Genetic Skeletal Disorders. The most common disease in the cohort was achondroplasia (28.9%), followed by osteogenesis imperfecta (18.4%), thanatophoric dysplasia (10.5%), chondrogenesis (7.9%), and 3-M syndrome (5.3%). The diagnostic yield in fetuses with isolated short long bones was lower than the fetuses with non-isolated short long bones, but not reached statistical significance (27.3% vs. 44.4%; = 0.151). Whereas, the rate in the fetuses with other skeletal abnormalities was significantly higher than those with non-skeletal abnormalities (59.4% vs. 32.5%, = 0.023), and the diagnostic rate was significantly higher in femur length (FL) below -4SDs group compared with FL 2-4SDs below GA group (72.5% vs. 16.7%; < 0.001). A long-term follow-up showed that outcomes for fetuses with FL 2-4SDs below GA were significantly better than those with FL below -4SDs. Additionally, fourteen (36.8%) novel short long bones-related variants were identified in the present study. The findings suggest that in fetuses with short long bones routine genetic tests failed to determine the underlying causes, exome sequencing could add clinically relevant information that could assist the clinical management of pregnancies. Novel pathogenic variants identified may broaden the mutation spectrum for the disorders and contributes to clinical consultation and subsequent pregnancy examination.
PubMed: 36923788
DOI: 10.3389/fgene.2023.1032346 -
Medicine Oct 2022Fetal skeletal anomalies are one of the most common and potentially pathogenic developmental abnormalities detected by ultrasound screening. Any suspected fetal skeletal...
RATIONALE
Fetal skeletal anomalies are one of the most common and potentially pathogenic developmental abnormalities detected by ultrasound screening. Any suspected fetal skeletal dysplasias often require further comprehensive evaluations.
PATIENT CONCERNS
Here 4 families with adverse fetal skeletal system histories were enrolled, including their histories of gestation, childbirth, familial skeletal abnormalities, and pregnancy outcomes. The corresponding diagnosis were done by whole exome sequencing (WES) combined with dynamic examination.
DIAGNOSIS
All of the families were definitively diagnosed through cytogenetics, molecular genetics, ultrasound, combined with multidisciplinary evaluation. Both of the fetuses in case 1 and case 2 were diagnosed with thanatophoric dysplasia type I, while the neonate in case 3 was diagnosed with Apert syndrome and a 3-years-old proband daughter with Crouzon syndrome in case 4.
INTERVENTIONS
We conducted karyotyping, copy number variation sequencing (CNV-seq), combined with WES to evaluate genetic conditions of abnormal fetus, neonate or proband patient. WES was preferred to obtain a relatively definitive diagnosis.
OUTCOMES
In cases 1 and 2, the families decided to choose termination of pregnancy due to fatal dysplasias. The couple in case 3, delivered a female baby diagnosed with Apert syndrome. Fortunately, in case 4, the family, which had a 3-years-old baby with Crouzon syndrome, gave birth to a healthy baby through prenatal diagnosis.
LESSONS SUBSECTIONS
Invasive prenatal diagnosis and dynamic assessments for the management of fetal skeletal dysplasias could contribute to revealing possible causes of fetal skeletal abnormalities and help clinicians conduct further genetic counseling in clinical practice.
Topics: Pregnancy; Infant, Newborn; Female; Humans; Child, Preschool; Exome Sequencing; DNA Copy Number Variations; Acrocephalosyndactylia; Fetus; Prenatal Diagnosis; Osteochondrodysplasias; Musculoskeletal Abnormalities; Craniofacial Dysostosis; Ultrasonography, Prenatal
PubMed: 36316869
DOI: 10.1097/MD.0000000000031321 -
International Medical Case Reports... 2022Spontaneous uterine rupture, especially in an unscarred uterus, is a rare pregnancy complication that can cause severe morbidity and mortality in both the mother and...
BACKGROUND AND IMPORTANCE
Spontaneous uterine rupture, especially in an unscarred uterus, is a rare pregnancy complication that can cause severe morbidity and mortality in both the mother and the fetus. The vast majority of uterine ruptures occur in the presence of a previous uterine scar, most commonly from a previous cesarean delivery. To our knowledge, here we reported the first case of spontaneous rupture of unscarred uterus in a term primigravida secondary to lethal skeletal dysplasia fetus (Type 1 Thanatophoric dysplasia) faced by a practicing clinician in an underdeveloped country (Somalia) with a successful outcome.
CASE PRESENTATION
The patient was 24 yrs. Old Primagravida, at 40 weeks gestation by LMP, presented with abdominal pain and active vaginal bleeding; she did not receive antenatal care during pregnancy; after initial abdominal ultrasonography and vaginal examination, laparotomy was performed due to high suspicion of uterine rupture. After dead fresh fetal extraction, the uterine defect was repaired successfully, and the patient was discharged home in good condition after several days.
CONCLUSION
Through this case, we would like to highlight the urgent need to focus on and recognize the importance of receiving antenatal care in the community so that the burden of thousands of lives lost each year can be reduced.
PubMed: 36225974
DOI: 10.2147/IMCRJ.S383195 -
Case Reports in Pediatrics 2022Thanatophoric dysplasia (TD) is a rare but uniformly lethal inherited disorder of the skeletal system resulting from defects in the fibroblast growth factor receptor-3...
Thanatophoric dysplasia (TD) is a rare but uniformly lethal inherited disorder of the skeletal system resulting from defects in the fibroblast growth factor receptor-3 gene on the short arm of chromosome ##4. It is characterised by pronounced shortening of the tubular bones resulting in significant short stature, macrocephaly, a funnel-shaped chest, protuberant abdomen, redundant skin in the limbs, and typical facies among others. The two clinical types of TD are differentiated by typical cranial and tubular bone configurations. Antenatal diagnosis is usually made in the last trimester and corroborated at birth. We present 2 cases of TD seen at Barau Dikko Teaching Hospital (BDTH) between January and August 2021 to highlight the potential difficulty with antenatal diagnosis, its diagnostic features, and associated early postnatal fatality. The antenatal diagnosis was missed in both cases in spite of repeated 2 and 3-trimester sonographic examinations. Both babies presented with remarkable micromelic short stature with the telephone-handle appearance of the femoral bones characteristic of type 1 TD, developed progressive respiratory distress at birth, and died within 36 hours of life despite respiratory support with Bubble CPAP. These cases are discussed along with a review of existing relevant literature.
PubMed: 36213390
DOI: 10.1155/2022/3056324 -
American Journal of Obstetrics and... Apr 2023This study aimed to determine the incremental yield of prenatal exome sequencing over chromosomal microarray or G-banding karyotype in fetuses with: (1) intrauterine... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
This study aimed to determine the incremental yield of prenatal exome sequencing over chromosomal microarray or G-banding karyotype in fetuses with: (1) intrauterine growth restriction related to placental insufficiency or (2) short long bones, in isolated and nonisolated instances for both scenarios.
DATA SOURCES
Data were collected via electronic searches for relevant citations from January 2010 to April 10, 2022 in MEDLINE, Embase, Web of Science, and Cochrane, and using relevant bibliographies and data generated in-house.
STUDY ELIGIBILITY CRITERIA
Included were prospective or retrospective cohort studies and/or case series with: (1) n>5 cases of short long bones and/or intrauterine growth restriction undergoing prenatal sequencing with a clearly defined phenotype including assessment of placental function; (2) testing based on prenatal phenotype only; (3) a nondiagnostic chromosomal microarray/karyotype; and (4) known results of genetic testing.
METHODS
Incremental yield was calculated for each study and as a pooled value for the aforementioned groups using a random-effects model. Results were displayed in forest plots with 95% confidence intervals. Heterogeneity was assessed statistically using Higgins' I. Publication bias was assessed graphically using funnel plots. Quality assessment was performed using modified Standards for Reporting of Diagnostic Accuracy criteria (International Prospective Register of Systematic Reviews registration number CRD42022324680).
RESULTS
Nineteen studies were included (n=452 cases). The apparent incremental yields with prenatal sequencing were: (1) 4% (95% confidence interval, -5.0 to 12; I=0%) in isolated intrauterine growth restriction with evidence of placental insufficiency, (2) 30% (95% confidence interval, 13-47; I=1%) in intrauterine growth restriction with additional structural anomalies, (3) 48% (95% confidence interval, 26-70; I=73%) in isolated short long bones, and (4) 68% (95% confidence interval, 58-77; I=51%) in short long bones with additional skeletal anomalies. Of the 37 short long bone cases with a diagnosis, 32 had a skeletal dysplasia, with thanatophoric dysplasia and osteogenesis imperfecta being the most common (both 21.6% [n=8/37]). In fetuses with short long bones and additional skeletal features, osteogenesis imperfecta was the most common diagnosis (28% [n=57/204]). Where documented, the inheritance patterns were de novo in 75.4% (n=150) of cases.
CONCLUSION
Prenatal sequencing adds substantially to incremental yield over chromosomal microarray in fetuses with short long bones or multisystem intrauterine growth restriction. Robust studies are required to assess the utility of fetal sequencing in isolated intrauterine growth restriction with evidence of placental insufficiency, which cannot be recommended on the basis of current evidence.
Topics: Humans; Pregnancy; Female; Fetal Growth Retardation; Placental Insufficiency; Exome Sequencing; Retrospective Studies; Osteogenesis Imperfecta; Placenta; Prenatal Diagnosis; Ultrasonography, Prenatal
PubMed: 36209938
DOI: 10.1016/j.ajog.2022.09.045 -
Annals of Pediatric Endocrinology &... Jun 2022Skeletal dysplasia is a diverse group of disorders that affect bone development and morphology. Currently, approximately 461 different genetic skeletal disorders have...
Skeletal dysplasia is a diverse group of disorders that affect bone development and morphology. Currently, approximately 461 different genetic skeletal disorders have been identified, with over 430 causative genes. Among these, fibroblast growth factor receptor 3 (FGFR3)-related skeletal dysplasia is a relatively common subgroup of skeletal dysplasia. Pediatric endocrinologists may encounter a suspected case of skeletal dysplasia in their practice, especially when evaluating children with short stature. Early and accurate diagnosis of FGFR3-related skeletal dysplasia is essential for timely management of complications and genetic counseling. This review summarizes 5 representative and distinct entities of skeletal dysplasia caused by pathogenic variants in FGFR3 and discusses emerging therapies for FGFR3-related skeletal dysplasias.
PubMed: 35793999
DOI: 10.6065/apem.2244114.057