The locomotor system
C. Simon Herrington in Muir's Textbook of Pathology, 2020
Achondroplasia is the most common skeletal dysplasia (1 in 15,000–40,000 livebirths) and is characterized by short stature. There is failure of enchondral ossification leading to diminished growth of the limbs. Achondroplasia is inherited in an autosomal dominant manner, and is due to a mutation of the fibroblast growth factor receptor 3 (FGFR3) gene on chromosome 4. This gene has a very high mutation rate, so >80% of affected children are born to normal parents. The mutation causes the receptor to be switched on, suppressing cartilage growth. Other mutations of this gene give rise to other rarer bone dysplasias. Patients with achondroplasia have distinctive features: the head appears large; the forehead is bulging, and the root of the nose is sunken. The limbs are disproportionately short compared with the trunk and cranium. The hands are broad with fingers of equal length (trident hands). The spinal canal is narrowed and spinal cord compression is common in adults. These changes are a consequence of the abnormal enchondral ossification. At the epiphyseal line the cartilage cells form short rows or are irregularly arranged, with little or no ossification, resulting in reduced bone growth.
Genetic Disorders, Dysplasias and Malformations
Louis Solomon, David Warwick, Selvadurai Nayagam in Apley and Solomon's Concise System of Orthopaedics and Trauma, 2014
MED is often confused with other childhood disorders which are associated with either lower-limb shortness or Perthes’-like changes in the epiphyses: Achondroplasia: marked by severe diminution in height and characteristic facial changes.Perthes’ disease: is confined to the hips and shows a typical cycle of changes from epiphyseal irregularity to fragmentation, flattening and healing.Hypothyroidism: if untreated, causes progressive and widespread epiphyseal dysplasia. However, these children have other clinical and biochemical abnormalities and have learning difficulties.
Telephone Receiver Femur
Michael E. Mulligan in Classic Radiologic Signs, 2020
Thantophoric dwarfism (thanatophoric dysplasia) was described in 1967 by Pierre Maroteaux and colleagues1 (Hopital des Enfants-Malades, Paris). They reported their findings in four cases and discussed the differential diagnostic features especially with regard to achondroplasia. One of the features they emphasized in this new disorder was the extreme shortening of the long bones. They also described the abnormal curvature of the diaphysis and the cupping, or flaring, and irregularity of the metaphysis (Figure 1). Four years later these abnormal features of the femurs were characterized as resembling a telephone receiver (Figure 2) by Joseph A. Bailey II (Johns Hopkins University) in his 1971 review article entided, Forms of Dwarfism Recognizable at Birth. Bailey said, ‘Affected individuals can be diagnosed even in utero on the basis of their characteristic bony deformities. Femurs shaped like ‘telephone receivers’ are an obvious feature.’2 Simply put by Bailey, ‘that’s the way it appeared to me’ (personal communication).
High-resolution computed tomography temporal bone imaging in achondroplasia
Published in Baylor University Medical Center Proceedings, 2021
Puneet S. Kochar, Priti Soin, Ayah Megahed
Achondroplasia is an autosomal dominant genetic disorder characterized by rhizomelic shortening, with a reported incidence of 15 to 125 per million live births.1 It is caused by a genetic defect, where amino acid arginine replaces glycine at position 380 in the gene that encodes fibroblast growth factor receptor 3 (FGFR3), resulting in abnormal endochondral ossification.2 In the head and neck region, this presents as macrocephaly with frontal bossing and depressed nasal bridge, giving the characteristic physical appearance.3 Several morphologic changes are seen on high-resolution computed tomography (HRCT) of the temporal bones that predispose patients to recurrent otitis media and hearing loss. These include “towering” of petrous ridges, upward tilting of the internal acoustic canal (IAC), vertical orientation of the geniculate ganglion, and a broad “ice cream cone” appearance of middle ear ossicles. We discuss these interesting HRCT findings.
Piloting and psychometric properties of a patient-reported outcome instrument for young people with achondroplasia based on the International Classification of Functioning Disability and Health: the Achondroplasia Personal Life Experience Scale (APLES)
Published in Disability and Rehabilitation, 2019
Janika Bloemeke, Rachel Sommer, Stefanie Witt, Michaela Dabs, Francisco Javier Badia, Monika Bullinger, Julia Quitmann
Moreover, the sample size in the pilot-test, as well as for the field-test was rather small. However, achondroplasia is a rare disease which presents a challenge in the recruitment of patients. Therefore, the field-test was also conducted in a sample of Spanish achondroplasia patients. A similar process is currently ongoing in the UK. Testing APLES in such a cross-cultural setting increases the international usefulness and applicability. Nevertheless, further studies with larger, more heterogeneous patient samples are needed to confirm the psychometric performance of the tool and its compliance with item response theory criteria. Furthermore, in a longitudinal validation process the responsiveness of the instrument needs to be assessed to detect clinical changes over time.
An Exploration of Sexual Health Education Among Individuals with Skeletal Dysplasia (Dwarfism)
Published in American Journal of Sexuality Education, 2018
The resulting participants included 199 females, 97 males, and 4 gender variant individuals. They ranged in age from 18 to 81 years (M = 41.7, SD = 15.54). The majority of the participants were Caucasian and heterosexual individuals, and about half of the sample were single (see Table 1). Of the four gender variant participants, three were Caucasian, one was African American, two were bisexual, one identified as asexual, one was gay, and three were single. Most participants resided in the United States (n = 253, 84%) or Canada (n = 26, 9%). Slightly over half of the sample reported that they have achondroplasia, and other diagnoses varied greatly (see Table 2).
Related Knowledge Centers
- Dwarfism
- Sleep Apnea
- Torso
- Macrocephaly
- Genetic Disorder
- Rhizomelia
- Skull Bossing
- Otitis
- Short-Limb Skeletal Dysplasia With Severe Combined Immunodeficiency
- Fibroblast Growth Factor Receptor 3