Achondrogenesis: A Lethal Chondrodystrophy.

Achondrogenesis is a type of skeletal dysplasia. Skeletal dysplasias are the heterogeneous class of bone growth disorders resulting in abnormal shape and size of the skeleton. Here, we present a rare case of achondrogenesis which was delivered by induced abortion at 6½ months of gestation. The physical, radiological, and ultrasonographic examinations done raised the possibility of this very rare anomaly. Achondrogensis is characterized by extreme micromelia and marked discrepancy between the relatively large head and the decreased trunk length. This rare condition has got genetic mutations associated with it. Achondrogenesis resembles other chondrodystrophies, therefore, its diagnosis needs to be made promptly and accurately.

Clinical, anthropometric, radiological and molecular characteristics of Egyptian achondroplasia patients

Achondroplasia is the most common form of non lethal skeletal dysphasia. It is a fully penetrant autosomal dominant disorder and the majority of cases are sporadic resulting from de novo mutations associated with advanced paternal age. The phenotype of achondroplasia is related to disturbance in endochondral bone formation due to mutations in the fibroblast growth factor receptor-3 [FGFR3] gene. Evaluation of the cardinal phenotypic features in achondroplasia, the body physique using anthropometric measurements, the characteristic radiological signs in the patients as a main tool for diagnosis and detection of the most common mutations in achondroplasia patients in the studied sample. From 42 cases referred to us as achondroplasia, we selected 20 cases where clinical manifestations were consistent with achondroplasia. Cases were subjected to full clinical examination, detailed anthropometric measurements, whole body skeletal survey and molecular studies of the most common mutations of the FGFR3 gene using PCR amplification technique. Nineteen cases were sporadic [95%] and one case had an affected father [5%]. A paternal age above 35 years at the time of child's birth was present in 7 cases [35%]. Paternal exposure to occupational heat was noted in 6 cases [30%] and parental exposure to chemicals in 3 cases [15%]. All cases showed typical clinical and radiological manifestations of achondroplasia. Anthropometric measurements quantitatively confirmed the body physique in the studied eases. G380R common mutations of the FGFR3 gene were detected in 15/18 cases [83%] with the G to A transition at nucleotide 1138 in 14 cases [77%]. Agenesis of corpus callosum, not previously reported in association with achondroplasia, was present in the only case with the G-C transversion mutation at nucleotide 1138 [5%]. Awareness of the cardinal features of achondroplasia, proper anthropometric measurements and detailed skeletal survey are the key for accurate diagnosis, genetic counseling and avoidance of over diagnosis. The majority of studied Egyptian achondroplasia patients have the same common mutation that has been most often defined in patients with achondroplasia from other countries

Real-time three dimensional sonographic features of an early third trimester fetus with achondrogenesis.

Generalized shortening of fetal long bones detected from prenatal sonographic examination usually raise a tentative diagnosis of skeletal dysplasia. Information obtained from grey-scale scan is frequently not sufficient to provide a definite diagnosis, and the images are not readily comprehensible for the parents-to-be. Lately, three-dimensional sonography has become increasing available in obstetric practice. The authors report here a rare case of fetal achondrogenesis, which is a lethal form of skeletal dysplasia, in a 30-week-old fetus using real-time three-dimensional ultrasound. The prenatal findings of fetal achondrogenesis from this technique were thoroughly described, along with postnatal radiography and autopsy results. Sonographic features from this imaging technique allow for an accurate diagnosis and better understanding of the parents. This facilitates the genetic counseling process, as well as the parental options for further care.

Prenatal diagnosis of achondroplasia.

A 25 years old lady came to Centre for Nuclear Medicine and Ultrasound, Mymensingh for ultrasonographic evaluation of gestational condition. Transabdominal ultrasonogram showed mal development of skeletal system with abnormally shortened limbs. This seems to be a case of achnodroplasia, which was proved subsequently true after termination of pregnancy.

Evaluation of newborns with skeletal dysplasias.

Skeletal dysplasia are a relatively common and distinct group of genetic disorders. Even though abnormalities of bone growth are the major clinical manifestations, the pathological process may involve in any body system. Many of these disorders have dire consequences such as neonatal death and most will have life-long physical and psychosocial morbidity associated with them. Recent advances in genetic research have identified the genes underlying the primary defects in several common skeletal dysplasias such as achondroplasia and diastrophic dysplasia. While these advances are clearly important in developing better therapy and a cure for those conditions, the role of the pediatrician as the diagnostician has remained unchanged. In this article we describe how a systematic approach using the simplest of tools--clinical assessment and radiograph--can arrive at a diagnosis in most instances of newborns with skeletal dysplasias. The key features that are essential for establishing a diagnosis for most of the entities encountered in the newborn are described along with our general approach to the evaluation of the radiographs.

Achondrogenesis type II (Langer-Saldino achondrogenesis): a case report

Achondrogenesis is a lethal form of congenital chondrodystrophy characterized by extreme micromelia. We describe a case of achondrogenesis type II (Langer-Saldino achondrogenesis) detected by prenatal ultrasonography at 20-week gestation. A dwarfed fetus with large head, short neck and chest, prominent abdomen and short limbs was terminated transvaginally. Radiologic and histopathologic examination revealed features of mild form of achondrogenesis type II. Although the case had no known risk factor and the phenotypic abnormality was mild, modern development in prenatal screening made the early detection possible.

Sonographic prenatal diagnosis of heterozygous achondroplasia: a case report.

A case of heterozygous achondroplasia diagnosed prenatally by sonographic examination at third trimester, demonstrating a large head, frontal bossing, low nasal bridge, shortening of the long bones (rhizomelic form), was presented and confirmed by neonatal physical examination and radiograph. Sonography has become the most sensitive and accurate method for detection of this abnormality. It displays the fetal biometry without distortion and permits accurate prenatal diagnosis. However, the prenatal diagnosis of this abnormality is very difficult until the third trimester of pregnancy.