ABSTRACT
Lens epithelial cell proliferation and differentiation are naturally well regulated and controlled, a characteristic essential for lens structure, symmetry and function. The effect of ionizing radiation on lens epithelial cell proliferation has been demonstrated in previous studies at high acute doses, but the effect of dose and dose rate on proliferation has not yet been considered. In this work, mice received single acute doses of 0.5, 1 and 2 Gy of radiation, at dose rates of 0.063 and 0.3 Gy/min. Eye lenses were isolated postirradiation at 30 min up until 14 days and flat-mounted. Then, cell proliferation rates were determined using biomarker Ki67. As expected, radiation increased cell proliferation 2 and 24 h postirradiation transiently (undetectable 14 days postirradiation) and was dose dependent (changes were very significant at 2 Gy; P = 0.008). A dose-rate effect did not reach significance in this study (P = 0.054). However, dose rate and lens epithelial cell region showed significant interactions (P < 0.001). These observations further our mechanistic understanding of how the lens responds to radiation.
Subject(s)
Lens, Crystalline/radiation effects , Animals , Cell Differentiation/radiation effects , Cell Proliferation/radiation effects , Dose-Response Relationship, Radiation , Epithelial Cells , Female , Humans , Mice, Inbred C57BL , Radiation Dosage , Radiation Exposure , Radiation, IonizingABSTRACT
Taybi-Linder syndrome (TALS, OMIM 210710) is a rare autosomal recessive disorder belonging to the group of microcephalic osteodysplastic primordial dwarfisms (MOPD). This syndrome is characterized by short stature, skeletal anomalies, severe microcephaly with brain malformations and facial dysmorphism, and is caused by mutations in RNU4ATAC. RNU4ATAC is transcribed into a non-coding small nuclear RNA which is a critical component of the minor spliceosome. We report here four foetuses and four unrelated patients with RNU4ATAC mutations. We provide antenatal descriptions of this rare syndrome including unusual features found in two twin foetuses with compound heterozygosity for two rare mutations who presented with mild intrauterine growth retardation and atypical dysmorphic facial features. We also carried out a literature review of the patients described up to now with RNU4ATAC mutations, affected either with TALS or Roifman syndrome, a recently described allelic disorder.
Subject(s)
Abnormalities, Multiple/genetics , Cardiomyopathies/genetics , Dwarfism/genetics , Fetal Growth Retardation/genetics , Immunologic Deficiency Syndromes/genetics , Mental Retardation, X-Linked/genetics , Microcephaly/genetics , Osteochondrodysplasias/genetics , RNA, Small Nuclear/genetics , Retinal Diseases/genetics , Abnormalities, Multiple/physiopathology , Alleles , Cardiomyopathies/physiopathology , Child , Child, Preschool , Dwarfism/physiopathology , Female , Fetal Growth Retardation/physiopathology , Fetus , Humans , Immunologic Deficiency Syndromes/physiopathology , Infant , Infant, Newborn , Male , Mental Retardation, X-Linked/physiopathology , Microcephaly/physiopathology , Mutation , Osteochondrodysplasias/physiopathology , Phenotype , Primary Immunodeficiency Diseases , Retinal Diseases/physiopathology , Spliceosomes/geneticsABSTRACT
The occurrence of mosaic ring chromosome 13 is rare. The mechanism of ring chromosome formation is usually associated with loss of genetic material. We report 2 cases of mosaic ring chromosome 13, resulting in deletion of 13qter. The first patient, a 15 year-old boy, presented a delayed psychomotor development, mental retardation, dysmorphic features and bleeding disorders associated with a de novo terminal 13q34 deletion. The second case was a foetus of 31 weeks with prenatal diagnosis of severe malformation such as holoprosencephaly, congenital cardiac defects, gastro-intestinal abnormalities with intrauterine growth retardation, the molecular analysis showed a de novo deletion encompassing the region 13q31.3-q34.
Subject(s)
Abnormalities, Multiple/genetics , Fetal Diseases/genetics , Adolescent , Adult , Chromosomes, Human, Pair 13/genetics , Female , Gestational Age , Humans , Karyotyping , Male , Pregnancy , Prenatal Diagnosis , Ring Chromosomes , Young AdultABSTRACT
Multiple Osteochondromas (MO) or hereditary multiple exostoses (HME) is an autosomal dominant skeletal disorder mainly characterized by multiple osteochondromas predominantly located at the growth plates of long bones. MO is a genetically heterogeneous disorder and results from mutations in EXT1 and EXT2 genes located on chromosome 8q23-q24 and 11p11-p12. We hereby report a case of a 23-year-old girl who presented characteristic clinical and radiological features of MO. The same clinical signs were observed in her relatives. The p.Arg340Cys mutation in the EXT1 gene was found in the proband confirming the clinical diagnosis. A surgical management was carried out in all affected bones which consisted of excision of the bigger and pain full osteochondromas. The patient was informed of her problem and genetic counseling was offered to the family's members
Subject(s)
Disease Management , Exostoses , Exostoses/genetics , PatientsABSTRACT
Down syndrome is the most common chromosomal abnormality in humans with an estimated incidence of one case in 770 live births. However; the occurrence of double aneuploidy involving autosome and or sex chromosome is a very rare phenomenon in lives born and the majority of reported cases are presented in form of spontaneous abortions. Here; we are reporting a case of a Rwandan patient with combination of trisomy 21 and triple X syndrome. The proband was 8-month-old female with typical features of Down syndrome. In additional to Down syndrome features; the child presented with minor features of triple X syndrome characterized by hypotonia and seizures
