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Cleidocranial dysplasia (CCD) is a rare hereditary disease of unknown etiology which was previously known as cleidocranial dysostosis. It usually follows an autosomal dominant mode of transmission with no predilection of genre or ethnic group. It is caused by a mutation of RUNX2, characterized by generalized dysplasia of the bones and teeth. Affected individuals have short stature, atypical facial features, and skeletal anomalies affecting mainly the skull and clavicle. The dental manifestations are mainly delayed exfoliation of the primary teeth and delayed eruption of the permanent teeth, with multiple impacted supernumeraries, and the absence of cellular cementum. The frequency of this disorder is 1 per million individuals. Here we report a rare case of CCD in a 23 year old female patient having most of the characteristic features of this syndrome.

Cleidocranial dysplasia (CCD) is a rare hereditary disease of unknown etiology which was previously known as cleidocranial dysostosis. It usually follows an autosomal dominant mode of transmission with no predilection of genre or ethnic group. It is caused by a mutation of RUNX2, characterized by generalized dysplasia of the bones and teeth. Affected individuals have short stature, atypical facial features, and skeletal anomalies affecting mainly the skull and clavicle. The dental manifestations are mainly delayed exfoliation of the primary teeth and delayed eruption of the permanent teeth, with multiple impacted supernumeraries, and the absence of cellular cementum. The frequency of this disorder is 1 per million individuals. Here we report a rare case of CCD in a 23 year old female patient having most of the characteristic features of this syndrome. [ABSTRACT FROM AUTHOR]

Mucopolysaccharidosis type 2 is a congenital lysosomal disease characterized by iduronate-2-sulfatase deficiency, which leads to excessive accumulation of glycosaminoglycans in tissue. Dysostosis, which primarily involves decreased bone mineralization with morphological changes in the bone, is a major skeletal condition in mucopolysaccharidosis, but its pathophysiology is not well known. Here, we report a case of mucopolysaccharidosis type 2 diagnosed at the age of 2 years with longitudinal follow-up data for more than 15 years. Although the patient underwent bone marrow transplantation, the developmental quotient did not improve, and cranial hyperostosis progressed prominently with a faintly dilated perivascular space. Other dysostoses and contraction of the joints were observed but did not improve either.

Crouzon syndrome is a rare genetic disorder. We report a rare case of Crouzon syndrome in a very young infant with distinct features of craniofacial malformations. A 10-week-old male child presented with features of craniofacial dysostosis with abnormal shape of the skull, proptosis, hypertelorism, curved nose and frontal bossing. Radiological findings revealed a predominant premature fusion of sagittal sutures. The infant had airway obstruction. Features of hydrocephalus, papilledema and optic atrophy were not evident. We chose to manage the symptoms and prevent complications, and the surgery was deferred for later, depending on the degree of malformation and psychological needs. Diagnosis of this rare condition at an early stage can help in preventing the development of complications. A careful follow-up and appropriate surgical intervention can improve the prognosis of this condition, which carries the risk of respiratory complications, poor vision and, in some cases, mental retardation as the age advances.

In 2019, the Nosology Committee of the International Skeletal Dysplasia Society provided an updated version of the Nosology and Classification of Genetic Skeletal Disorders. This is a reference list of recognized diseases in humans and their causal genes published to help clinician diagnosis and scientific research advances. Complementary to mammalian models, zebrafish has emerged as an interesting species to evaluate chemical treatments against these human skeletal disorders. Due to its versatility and the low cost of experiments, more than 80 models are currently available. In this article, we review the state-of-art of this “aquarium to bedside” approach describing the models according to the list provided by the Nosology Committee. With this, we intend to stimulate research in the appropriate direction to efficiently meet the actual needs of clinicians under the scope of the Nosology Committee.

In 2019, the Nosology Committee of the International Skeletal Dysplasia Society provided an updated version of the Nosology and Classification of Genetic Skeletal Disorders. This is a reference list of recognized diseases in humans and their causal genes published to help clinician diagnosis and scientific research advances. Complementary to mammalian models, zebrafish has emerged as an interesting species to evaluate chemical treatments against these human skeletal disorders. Due to its versatility and the low cost of experiments, more than 80 models are currently available. In this article, we review the state-of-art of this "aquarium to bedside" approach describing the models according to the list provided by the Nosology Committee. With this, we intend to stimulate research in the appropriate direction to efficiently meet the actual needs of clinicians under the scope of the Nosology Committee. [ABSTRACT FROM AUTHOR]

Background: Acrodysostosis is a rare hereditary disorder described as a primary bone dysplasia with or without hormonal resistance. Pathogenic variants in the PRKAR1A and PDE4D genes are known genetic causes of this condition. The latter gene variants are more frequently identified in patients with midfacial and nasal hypoplasia and neurological involvement. The aim of our study was to analyse and confirm a genetic cause of acrodysostosis in a male patient. Case presentation: We report on a 29-year-old Lithuanian man diagnosed with acrodysostosis type 2. The characteristic phenotype includes specific skeletal abnormalities, facial dysostosis, mild intellectual disability and metabolic syndrome. Using patient's DNA extracted from peripheral blood sample, the novel, likely pathogenic, heterozygous de novo variant NM_001104631.2:c.581G > C was identified in the gene PDE4D via Sanger sequencing. This variant causes amino acid change (NP_001098101.1:p.(Arg194Pro)) in the functionally relevant upstream conserved region 1 domain of PDE4D. Conclusions: This report further expands the knowledge of the consequences of missense variants in PDE4D that affect the upstream conserved region 1 regulatory domain and indicates that pathogenic variants of the gene PDE4D play an important role in the pathogenesis mechanism of acrodysostosis type 2 without significant hormonal resistance. [ABSTRACT FROM AUTHOR]

Mucopolysaccharidosis type I is inherited in an autosomal recessive manner and results from the defective activity of the enzyme alpha-L-iduronidase, which leads to the accumulation of glycosaminoglycans (mainly heparan and dermatan sulfate) in the lysosomes and further multiple organ dysfunction. This severe genetic progressive disease can be detected at an early age by skeletal deformities and phenotypic data. Early enzyme replacement therapy and/or bone marrow transplantation can slow down irreversible damages to various organs and systems or reduce their severity and improve the quality of life for a child.

Introduction: Cleidocranial dysplasia (CCD) is an autosomal dominant disorder primarily affecting bones, which undergo membranous ossification. It commonly presents with significant dental and facial problems, including the hypoplastic maxilla, retained primary teeth, unerupted permanent teeth and supernumerary teeth. It is usually diagnosed based on clinical and radiographic findings, which are pathognomic. Here, we report clinical and radiographic findings of 7 patients with CCD who reported to our Institute during 2013-2014. Results: Age of patient ranged from 13 to 55 years, out of which 5 were males and 2 were females. Characteristic clinical findings, which were present in all cases include frontal and parietal bossing, brachycephalic skull, hypertelorism, broad nasal bridge and shoulder hypermobility. Radiographic findings seen were hypoplasia/aplasia of the clavicle, open skull suture, wide, open fontanel, and the presence of impacted permanent and supernumerary teeth. In one case, there was follicular cyst associated with impacted mandibular canine. Conclusion: Successful treatment involves a multidisciplinary approach and involves timely diagnosis at an early stage of development

Introduction. Patients with spondylocostal dysostosis (SCD) have congenital spine and rib deformities associated with frequently severe thoracic insufficiency and respiratory compromise. The literature is largely composed of case reports and small cohorts, and there is little information regarding adults with this condition. In this report, we describe the natural history of a conservatively treated patient and include quality-of-life issues such as childbearing, athletic participation, and occupational selection. Case Presentation. We present a patient with SCD who was conservatively treated by a single physician from birth for 31 years. Our patient was capable of a reasonably good quality of life through adulthood, including participation in gymnastics and employment. At age 18, she became pregnant and subsequently terminated the pregnancy due to obstetrical concerns for compromised respiration. She has had intermittent respiratory complaints and occasionally experiences dyspnea with exertion, but this only has limited her during certain activities in the past three years. Currently, she takes naproxen for chronic back pain with periodic exacerbations. Discussion. Other cases in the literature have described adult SCD patients who have received nonoperative treatment and achieved a wide range of functional outcomes. This provides some limited evidence to suggest that select patients with SCD may be treated conservatively and achieve a reasonable quality of life. However, close clinical follow-up with these patients is recommended, particularly early on, considering the high rates of infant morbidity and mortality. Chest physiotherapy and early pulmonary care have been associated with favorable outcomes in infancy. Surgery to increase thoracic volume and correct scoliosis has been shown in some cases to improve respiratory function. Treatment depends on the degree of thoracic insufficiency and quality of life. The natural history of SCD remains largely unknown, but some patients are capable of relatively favorable life spans, employment, and participation in athletics. [ABSTRACT FROM AUTHOR]

Aim: Mucopolysaccharidosis Type IVA (MPS IVA), Morquio A, is caused by the deficiency in lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase. Multisystemic involvements include skeletal systems, pulmonary disease, valvular heart disease, hearing loss, mild hepatomegaly, corneal clouding, coarse facial features. Materials and Methods: We retrospectively analyzed clinical and laboratory and follow up findings of our 25 patients with ministry for primary industries independent verification agency. Results: Mean age of the patients was 14.9±7.05 (5.5-36 years). Mean age at diagnosis was 7.3±6.2 years (6 months-31 years). Female: male ratio was 13/12. All patients had skeletal manifestation and X-ray analysis demonstrated "dysostosis multiplex". Twelve patients (48%) had cardiac valve disease. Twenty three (92%) patients had corneal clouding, 15 (60%) patients had hearing loss and 9 (36%) had hepatomegaly. Six (24%) patients were unable to walk. Mean follow up period is 7.4 years ±3.5 years (3 months-17 years). Four patients have not visit our clinical for last =3 years. Three patients died during follow up. Conclusion: MPS IVA is a severe disorder and is usually fatal in the second or third decade of life due to the complications of the disease. Early diagnosis of the patient became more important, because specific therapy with elasulphase alpha was approved recent years ago. [ABSTRACT FROM AUTHOR]

Proximal 16p11.2 microdeletions are recurrent microdeletions with an overall prevalence of 0.03%. In patients with segmentation defects of the vertebra ( SDV), a burden of this microdeletion was observed with TBX6 as a candidate gene for SDV. In a published cohort of patients with congenital scoliosis ( CS), TBX6 haploinsufficiency was compound heterozygous with a common haplotype. Besides, a single three-generation family with spondylocostal dysostosis ( SCD) was reported with a heterozygous stop-loss of TBX6. These observations questioned both on the inheritance mode and on the variable expressivity associated with TBX6-associated SDV. Based on a national recruitment of 56 patients with SDV, we describe four patients with variable SDV ranging from CS to SCD associated with biallelic variations of TBX6. Two patients with CS were carrying a proximal 16p11.2 microdeletion associated with the previously reported haplotype. One patient with extensive SDV was carrying a proximal 16p11.2 microdeletion associated with a TBX6 rare missense change. One patient with a clinical diagnosis of SCD was compound heterozygous for two TBX6 rare missense changes. The three rare variants were affecting the chromatin-binding domain. Our data illustrate the variable expressivity of recessive TBX6 ranging from CS to SCD. [ABSTRACT FROM AUTHOR]

Ischiospinal Dysostosis (ISD) is a complex and very rare medical entity. It is associated with kyphoscoliosis, dysplasia or aplasia of the ischial rami, segmental anomalies of the bony vertebrae, and peculiar facial morphologies. In this case report, we present a child with Ischiospinal Dysostosis and Pierre-Robin Syndrome. This case report is unique as we followed the patient for 13 years in which he had multiple spinal procedures to treat his kyphoscoliosis. In this paper, we elucidated the number of case reports with documented follow-up regarding spinal cord injury or other complications of ISD and its management. [ABSTRACT FROM AUTHOR]

The acrofacial dysostoses (AFD) are a genetically heterogeneous group of inherited disorders with craniofacial and limb abnormalities. Rodriguez syndrome is a severe, usually perinatal lethal AFD, characterized by severe retrognathia, oligodactyly and lower limb abnormalities. Rodriguez syndrome has been proposed to be a severe form of Nager syndrome, a non-lethal AFD that results from mutations in SF3B4, a component of the U2 small nuclear ribonucleoprotein particle (U2 snRNP). Furthermore, a case with a phenotype intermediate between Rodriguez and Nager syndromes has been shown to have an SF3B4 mutation. We identified heterozygosity for SF3B4 mutations in Rodriguez syndrome, confirming that the phenotype is a dominant disorder that is allelic with Nager syndrome. The mutations led to reduced SF3B4 synthesis and defects in mRNA splicing, primarily exon skipping. The mutations also led to reduced expression in growth plate chondrocytes of target genes, including the DLX5, DLX6, SOX9, and SOX6 transcription factor genes, which are known to be important for skeletal development. These data provide mechanistic insight toward understanding how SF3B4 mutations lead to the skeletal abnormalities observed in the acrofacial dysostoses. [ABSTRACT FROM AUTHOR]

Acromelic frontonasal dysostosis ( AFND) is a distinctive and rare frontonasal malformation that presents in combination with brain and limb abnormalities. A single recurrent heterozygous missense substitution in ZSWIM6, encoding a protein of unknown function, was previously shown to underlie this disorder in four unrelated cases. Here we describe four additional individuals from three families, comprising two sporadic subjects (one of whom had no limb malformation) and a mildly affected female with a severely affected son. In the latter family we demonstrate parental mosaicism through deep sequencing of DNA isolated from a variety of tissues, which each contain different levels of mutation. This has important implications for genetic counselling. [ABSTRACT FROM AUTHOR]

α-Fucosidosis is a rare inherited neuro-degenerative disorder causing progressive neurological deterioration leading to early death. Definitive diagnosis requires α-fucosidase enzyme assay or FUCA1 gene testing, which being expensive limits the definitive diagnosis in resource limited countries. We present two siblings with classic symptoms, radiological and MRI brain findings suggestive of α-fucosidosis and a clinical approach to reach to the diagnosis. [ABSTRACT FROM AUTHOR]

The highly conserved Notch-signaling pathway mediates cell-to-cell communication and is pivotal for multiple developmental processes and tissue homeostasis in adult organisms. Notch receptors and their ligands are transmembrane proteins with multiple epidermal-growth-factor-like (EGF) repeats in their extracellular domains. In vitro the EGF repeats of mammalian ligands that are essential for Notch activation have been defined. However, in vivo the significance of the structural integrity of each EGF repeat in the ligand ectodomain for ligand function is still unclear. Here, we analyzed the mouse Notch ligand DLL1. We expressed DLL1 proteins with mutations disrupting disulfide bridges in each individual EGF repeat from single-copy transgenes in the HPRT locus of embryonic stem cells. In Notch transactivation assays all mutations impinged on DLL1 function and affected both NOTCH1 and NOTCH2 receptors similarly. An allelic series in mice that carried the same point mutations in endogenous Dll1, generated using a mini-gene strategy, showed that early developmental processes depending on DLL1-mediated NOTCH activation were differently sensitive to mutation of individual EGF repeats in DLL1. Notably, some mutations affected only somite patterning and resulted in vertebral column defects resembling spondylocostal dysostosis. In conclusion, the structural integrity of each individual EGF repeat in the extracellular domain of DLL1 is necessary for full DLL1 activity, and certain mutations in Dll1 might contribute to spondylocostal dysostosis in humans. [ABSTRACT FROM AUTHOR]

Ischiospinal dysostosis (ISD) is a polytopic dysostosis characterized by ischial hypoplasia, multiple segmental anomalies of the cervicothoracic spine, hypoplasia of the lumbrosacral spine and occasionally associated with nephroblastomatosis. ISD is similar to, but milder than the lethal/semilethal condition termed diaphanospondylodysostosis (DSD), which is associated with homozygous or compound heterozygous mutations of bone morphogenetic protein-binding endothelial regulator protein (BMPER) gene. Here we report for the first time biallelic BMPER mutations in two patients with ISD, neither of whom had renal abnormalities. Our data supports and further extends the phenotypic variability of BMPER-related skeletal disorders. [ABSTRACT FROM AUTHOR]

Introduction: dysostosis spondylothoracic, or Jarcho Levin syndrome, is characterized by a short neck and thorax, a protruding abdomen, abnormal vertebral segmentation and fusion posterior costal resulting in thoracic restriction or respiratory failure and scoliosis. The prevalence is estimated at 1 in 12,000 live births for the people of Puerto Rico and 1 per 200,000 for the rest of the world. It is inherited in an autosomal recessive manner and the only related gene is MESP2. Clinical case: Newborn male, who during the first hour of life develops perioral cyanosis, thoracoabdominal dissociation and polipnea, requiring endotracheal intubation and mechanical ventilation for respiratory impairment, finding thoracoabdominal costovertebral abnormalities with an x-ray, and a conditioning restrictive pattern like a crab. During the physical examination, we found horizontal eyelid openings, right atrial appendage, straight nasal bridge, short thorax and asymmetry and hypertrichosis, predominantly in the back. A diagnosis of dysostosis spondylothoracic is confirmed, and the patient was discharged at 7 days of age, with follow up neonatal consultation at high risk. Conclusion: In a neonate with respiratory distress syndrome, costovertebral assessment becomes important, with the intention of discarding syndromes associated with defects in the costovertebral segmentation, as Jarcho Levin syndrome, which causes respiratory impairment that can lead to respiratory failure and death. [ABSTRACT FROM AUTHOR]

Nager syndrome is a rare syndrome resulting from developmental abnormalities of the first and second branchial arches. Nager syndrome is rare and mostly sporadic. The main clinical features consist of craniofacial, limb, and musculoskeletal morphogenesis. These findings included malar hypoplasia, maxillomandibular hypoplasia, micrognathia, downslanting palpebral fissures, cleft palate, ear anomalies, hypoplastic thumb, short forearm, proximal radioulnar synostosis, atrial septal defect, lower limb deformities, and flat nasal bridge. The prevalence is unknown; about 100 cases of Nager syndrome have been published up to now. Patients with Nager syndrome are found worldwide among all racial and ethnic groups. Trismus and glossoptosis resulting in oropharyngeal airway narrowing cause life-threatening respiratory distress for patients with Nager syndrome. In this case report, dental rehabilitation of a 10-year-old child with Nager syndrome is presented. [ABSTRACT FROM AUTHOR]

Cleidocranial dysplasia (CCD) is a rare autosomal dominant condition with generalized dysplasia of bone characterized by delayed closure of cranial sutures, hypoplastic or aplastic clavicles, short stature, dental abnormalities and a variety of other skeletal abnormalities. We report two cases presenting with classical features of CCD because of its rarity. [ABSTRACT FROM AUTHOR]

Pycnodysostosis is a rare sclerosing bone disorder characterized by short stature, brachycephaly, short/stubby fingers, open cranial sutures/fontanelle, and diffuse osteosclerosis, where multiple fractures of long bones and osteomyelitis of the jaw are common complications. We present a rare case of pycnodysostosis with chronic suppurative osteomyelitis of the mandible in a 36-year-old woman; which was nonsurgically managed by a conservative approach involving a novel protocol referred to as intra-lesional antibiotic therapy. [ABSTRACT FROM AUTHOR]

The article describes the case of surgical correction of severe kyphoscoliosis resulting in a neurological complication in Marshall-Smith syndrome (MSS). MSS is a rare syndrome described by facial dysostosis, respiratory difficulties, mental retardation, and short height. MSS is thought to be linked to NFIX gene mutation.

Casamassima Morton Nance Syndrome (CMNS) is an extraordinary entity, of unknown aetiology and poor prognosis, which belongs to the heterogeneous group of spondylocostal dysostosis. The syndrome is characterized by costal and vertebral anomalies, anal atresia and genitourinary defects, such as cryptorchidism, hydrocele, hydronephrosis, renal agenesis, cloaca and urinary fistula, among others. In this work we report a 6 year-old girl, no history of consanguinity and with normal karyotype, presenting costovertebral, anal and urogenital congenital defects, consistent with CMNS. In the evolution of the disease, the patient presented severe psychomotor delay, epilepsy and relapsing renal lithiasis. These findings have not been mentioned in the previous reports, probably due to short survival. The causal mechanisms proposed are autosomal recessive inheritance, de novo mutations and chromosomal rearrangements, present in at least two cases. This report illustrates the possibility of achieving a longer survival, up to scholar age, by an early multidisciplinary approach, although the syndrome may cause severe psychomotor delay. The aetiology remains unknown, perhaps being heterogeneous, which makes these patients suitable for comparative genomic hybridization to microarrays or exome sequencing. [ABSTRACT FROM AUTHOR]

Jarcho-Levin syndrome (JLS) is a rare congenital dysostosis characterized by multiple vertebral and costal anomalies. The combination of JLS and neural tube defect is rare. Only six cases of JLS accompanying diastematomyelia have been reported; all were in infants or children. We present the case of a 37-year-old female patient with JLS who also had diastematomyelia in lumbar vertebral level. This is the seventh case of JLS with diastematomyelia, and the first adult case. [ABSTRACT FROM AUTHOR]

Pyknodysostosis is a rare, genetic, autosomal recessive condition characterized by short stature, generalized bone sclerosis, and oral manifestations such as maxillary atresia and an increase of the mandibular angle. The main purpose of this article was to report a case of pyknodysostosis, describing the characteristic orofacial findings of the disease and discussing the differential diagnosis.

Nager syndrome belongs to the group of acrofacial dysostosis, which are characterized by the association of craniofacial and limb malformations. Recently, exome sequencing studies identified the SF3B4 gene as the cause of this condition in most patients. SF3B4 encodes a highly conserved protein implicated in mRNA splicing and bone morphogenic protein ( BMP) signaling. We performed SF3B4 sequencing in 14 families (18 patients) whose features were suggestive of Nager syndrome and found nine mutations predicted to result in loss-of-function. SF3B4 is the major gene responsible for autosomal dominant Nager syndrome. All mutations reported predict null alleles, therefore precluding genotype-phenotype correlations. Most mutation-negative patients were phenotypically indistinguishable from patients with mutations, suggesting genetic heterogeneity. [ABSTRACT FROM AUTHOR]

Whole-exome sequencing ( WES) has proven its utility in finding novel genes associated with rare conditions and its usefulness is being further demonstrated in expanding the phenotypes of well known diseases. We present here a family with a previously undiagnosed X-linked condition characterized by progressive restriction of joint range of motion, prominence of the supraorbital ridge, audiology issues and hernias. They had an average stature, normal occipitofrontal circumference and intelligence, absence of dysostosis multiplex and otherwise good health. A diagnosis of Hunter syndrome was determined using WES and further supported by biochemical investigations. The phenotype of this family does not correspond to either the severe or attenuated clinical subtypes of Hunter syndrome. As further atypical families are reported, this classification will need to be modified. Our findings highlight the utility of WES in expanding the recognized phenotypic spectrum of known syndromes. [ABSTRACT FROM AUTHOR]

Background & objectives: Multiple suphphatase deficiency (MSD) is an autosomal recessive disorder affecting the post translational activation of all enzymes of the sulphatase family. To date, approximately 30 different mutations have been identified in the causative gene, sulfatase modifying factor 1 (SUMF1). We describe here the mutation analysis of a case of MSD. Methods: The proband was a four year old boy with developmental delay followed by neuroregression. He had coarse facies, appendicular hypertonia, truncal ataxia and ichthyosis limited to both lower limbs. Radiographs showed dysostosis multiplex. Clinical suspicion of MSD was confirmed by enzyme analysis of four enzymes of the sulphatase group. Results: The patient was compound heterozygote for a c.451A>G (p.K151E) substitution in exon 3 and a single base insertion mutation (c.690_691 InsT) in exon 5 in the SUMF1 gene. The bioinformatic analysis of the missense mutation revealed no apparent effect on the overall structure. However, the mutated 151-amino acid residue was found to be adjacent to the substrate binding and the active site residues, thereby affecting the substrate binding and/or catalytic activity, resulting in almost complete loss of enzyme function. Conclusions: The two mutations identified in the present case were novel. This is perhaps the first report of an insertion mutation in SUMF1 causing premature truncation of the protein. [ABSTRACT FROM AUTHOR]

Background To characterize cathepsin K (CTSK) mutations in a group of patients with pycnodysostosis, who presented with either short stature or atypical fractures to pediatric endocrinology or dysmorphic features to pediatric genetics clinics. Methods Seven exons and exon/intron boundaries of CTSK gene for the children and their families were amplified with PCR and sequenced. Sixteen patients from 14 families with pycnodysostosis, presenting with typical dysmorphic features, short stature, frequent fractures and osteosclerosis, were included in the study. Results We identified five missense mutations (M1I, I249T, L7P, D80Y and D169N), one nonsense mutation (R312X) and one 301 bp insertion in intron 7, which is revealed as Alu sequence; among them, only L7P and I249 were described previously. The mutations were homozygous in all cases, and the families mostly originated from the region where consanguineous marriage rate is the highest. Patients with M1I mutation had fractures, at younger ages than the other pycnodysostosis cases in our cohort which were most probably related to the severity of mutation, since M1I initiates the translation, and mutation might lead to the complete absence of the protein. The typical finding of pycnodysostosis and acroosteolysis could not be detected in two patients, although other patients carrying the same mutations had acroosteolysis. Additionally, none of the previously described hot spot mutations were seen in our cohort; indeed, L7P and R312X were the most frequently detected mutations. Conclusions We described a large cohort of pycnodysostosis patients with genetic and phenotypic features, and, first Alu sequence insertion in pycnodysostosis. [ABSTRACT FROM AUTHOR]

In this review, we discuss aspects of the prenatal diagnosis of fetal skeletal malformations, concentrating on the advantages offered by different imaging techniques and the approaches that are of value in evaluating a suspected skeletal dysplasia. We also briefly address the findings in some of the commoner malformations of the fetal skeleton that may be encountered. [ABSTRACT FROM AUTHOR]

During the summer of 2013 seven Italian Tyrolean Grey calves were born with abnormally short limbs. Detailed clinical and pathological examination revealed similarities to chondrodysplastic dwarfism. Pedigree analysis showed a common founder, assuming autosomal monogenic recessive transmission of the defective allele. A positional cloning approach combining genome wide association and homozygosity mapping identified a single 1.6 Mb genomic region on BTA 6 that was associated with the disease. Whole genome re-sequencing of an affected calf revealed a single candidate causal mutation in the Ellis van Creveld syndrome 2 (EVC2) gene. This gene is known to be associated with chondrodysplastic dwarfism in Japanese Brown cattle, and dwarfism, abnormal nails and teeth, and dysostosis in humans with Ellis-van Creveld syndrome. Sanger sequencing confirmed the presence of a 2 bp deletion in exon 19 (c.2993_2994ACdel) that led to a premature stop codon in the coding sequence of bovine EVC2, and was concordant with the recessive pattern of inheritance in affected and carrier animals. This loss of function mutation confirms the important role of EVC2 in bone development. Genetic testing can now be used to eliminate this form of chondrodysplastic dwarfism from Tyrolean Grey cattle. [ABSTRACT FROM AUTHOR]

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