Achondroplasia Clinical Presentation

  • Author: Shital Parikh, MD; Chief Editor: Dennis P Grogan, MD   more...
 
Updated: Mar 21, 2012
 

History

  • Gross motor development frequently is delayed. Motor milestones such as head control and independent sitting, standing, and ambulation may lag by 3-6 months. Speech and language problems may be caused by tongue thrust (due to abnormal maxillomandibular relationship) but often resolve spontaneously. Twenty percent of patients experience delayed speech acquisition. Cognitive skills are preserved, and the intelligence level is within normal limits. Cranial enlargement and poor head control place the infant at risk for extension injuries. An Australian study assessed the functional milestones of achondroplasia children aged 3-7 years. The data noted that while milestones were delayed across all ages studied, functioning improved between age 3 and 5 years, although not subsequently. Access to clinicians skilled in achondroplasia management may assist these children to become more independent.[10, 11]
  • Standing height is below the third percentile for both sexes. The mean adult standing height for men is 132 cm (52 in), and that for women is 125 cm (49 in). Sitting height, a reflection of trunk length, is within normal limits.
  • Seventy-five percent of patients have otitis media when younger than 5 years. Recurrent otitis media is common due to poor drainage of the eustachian tubes from underdevelopment of the midface, relative hypertrophy of tonsils and adenoids, and temporal bone abnormalities. Conductive hearing loss is present due to ossicular chain stiffness, and may be either congenital or acquired due to recurrent otitis media. Sensorineural hearing loss may be present in a few patients. Maxillary hypoplasia may lead to dental crowding and malocclusion.
  • Upper airway obstruction, small chest wall, pectus excavatum, and neurogenic effects from brain stem compression reduce the vital capacity. Incidence of pneumonia, cyanotic spells, apnea, and other respiratory complications is increased. Symptoms of airway obstruction include snoring and sleeping with the neck in a hyperextended position.
  • Abnormal development of the base of the skull results in a foramen magnum that is smaller than in average individuals. Narrowing of the foramen magnum compresses the cervicomedullary region, causing symptoms of respiratory insufficiency, apnea, cyanotic episodes, feeding problems, quadriparesis, and sudden death. These symptoms are common in the first several years of life because of the failure of the anticipated enlargement of foramen magnum during infancy and childhood. Chronic brain stem compression also may be a cause of hypotonia observed in the first 2 years of life.
  • Stenosis of the spinal canal and intervertebral foramen leads to symptoms such as low back pain, leg pain, dysesthesia, paresthesia, paraparesis, incontinence, and neurogenic claudication. Claudication may present as vague symptoms of aching or tiredness of the lower extremities induced by walking or standing. Symptoms may progress with a sensation of tingling and numbness and, eventually, weakness. Often, the pain is alleviated if the patient assumes a squatting position or bends forward.
  • More than 50% of patients experience symptoms of lower extremity radiculopathy from nerve root compression or cauda equina syndrome. The mean age of onset of back or lower extremity symptoms is 26 years; one third of patients are younger than 15 years at onset.
  • Symptoms due to abnormal curvature of the spine (eg, kyphosis, lordosis, scoliosis) may be present, such as deformity, back pain, respiratory dysfunction, neurologic involvement, or symptoms of spinal stenosis. The incidence of kyphoscoliosis may be as high as 33-50% in adults. However, the curve magnitude is generally less than 30° and generally does not require treatment.
  • Joint laxity may be present in children. Genu recurvatum is common. As the child grows, genu varum (tibial bowing) and lateral tibial torsion become apparent.
  • Macrocephaly represents ventriculomegaly or arrested hydrocephalus.
  • Mild but annoying neurologic disturbances can be attributed to local anatomic abnormalities and abnormal stretching of nerves. Examples include hip and knee pain from meralgia paresthetica, ankle pain from irritation of the peroneal nerve, or facial pain due to trigeminal neuralgia.
  • Fibromyalgia (trigger points located in the lower part of the back) and trochanteric bursitis can be seen in some patients.
Next

Physical

  • Achondroplasia is evident at birth as a disproportionate short-limb dwarfing condition (see image below). Characteristics include an enlarged neurocranium, frontal bossing, flattening of the nasal bridge, midface hypoplasia, and a relatively prominent mandible. The anteroposterior diameter of the chest is flattened, the lower ribs are flared, and the abdomen protrudes. Typical features of a person with achondroplastic Typical features of a person with achondroplastic dwarfism, including normal trunk with rhizomelic shortening and genu varum.
  • Before walking, the child has a thoracolumbar kyphosis and lordosis in the interscapular thoracic region.[12] The kyphosis can be severe in the sitting position and may not reduce completely in the prone position. Once independent ambulation is established, an exaggerated lumbar lordosis with forward rotation of the pelvis develops, and the spinal deformity is associated with hip flexion contractures and a prominent abdomen and buttocks. However, some degree of kyphosis persists in 25% of adults.
  • The upper extremity involvement is rhizomelic, with the proximal segments more severely affected than the distal segments. The shoulders appear broad due to normal development of clavicle and well-developed musculature. The short arms may contribute to bulky muscle mass and apparent increased strength in such individuals. Loss of full extension of the elbow, ranging from 15-30°, is present. A trident hand is common and is characterized by a persistent space between the long and ring fingers when approximation of the fingers is attempted in full extension. The fingertips reach the level of the hips, which causes difficulty with hygiene and dressing.
  • Lower extremity involvement is rhizomelic, with hip flexion contractures, ligamentous laxity and external rotation of the extremity, and genu recurvatum before walking age. The tibia is bowed, resulting in significant genu varum and some degree of ankle varus. Frequently, gaping of the lateral compartment or lateral translation of the tibia on the femur can be seen during the stance phase. Occasionally, a valgus deformity may develop. The gait is usually a waddling gait, and circumduction motion of the hips and lower extremities occurs when running is attempted.
  • Spinal deformities are the most common and potentially disabling problems.[13, 14, 15] Spinal canal stenosis and stenosis of the intervertebral foramen are secondary to short thickened pedicles, interpedicular narrowing, thickened laminae, intervertebral disc herniation, degenerative spondylolysis, excessive lumbar lordosis, or anterior wedging of the vertebral bodies from thoracolumbar kyphosis. Sensory deficits, posterior column dysfunction, lower and upper motor neuron signs, and signs of neurologic claudication may be present. Signs of lower extremity radiculopathy from nerve root compression or cauda equina syndrome are present in more than 50% of patients.
  • Macrocephaly is present due to triventricular enlargement and hydrocephalus.[16] However, intracranial pressure is not elevated significantly. In infants, a rough estimate of the pressure can be made by palpating the fontanelles.
Previous
Next

Causes

  • Genetic basis for achondroplasia[17]
    • A single gene mapped to the short arm of the fourth chromosome (band 4p16.3) is responsible for achondroplasia and is transmitted as an autosomal dominant trait.
    • At least 80% of cases result from a random new mutation. In sporadic cases, a paternal age older than 36 years is common. Most parents are of average size and have no family history of a dwarfing condition. The risk of the parents producing a second affected child is almost negligible. Reports have estimated that there is a 1 in 443 risk of recurrence of achondroplasia in the siblings of an affected child with unaffected parents. This is because of gonadal mosaicism in the parents. Average-sized siblings have no increased risk of producing a child with achondroplasia. When both parents have achondroplasia, 50% of their offspring are heterozygous and affected, 25% are homozygous, which is ordinarily fatal in the first few months of life, and 25% are unaffected. When one parent has achondroplasia, the chance of transmitting this gene to each child is 50%.
  • Molecular basis of achondroplasia
    • Fibroblast growth factors are structurally related proteins associated with cell growth, migration, wound healing, and angiogenesis. At the cellular level, their function is mediated by transmembrane tyrosine kinase receptors, known as fibroblast growth factor receptors (FGFR).[18]
    • Mutation in FGFR3 is responsible for achondroplasia, hypochondroplasia, and thanatophoric dysplasia.[18] The primary function of FGFR3 is to limit osteogenesis. Mutation causes enhancement in its function of limiting endochondral ossification. Mutation in FGFR3 in achondroplasia is due to transition of guanine to adenine (G to A) at nucleotide 1138 of complimentary DNA.
  • Two reports exist of achondroplasia associated with Down syndrome.[19] The calculated risk of association is 1 case in every 8 years in the United States, based on the current birth rate.
Previous
Proceed to Differential Diagnoses
 
 
Contributor Information and Disclosures
Author

Shital Parikh, MD  Assistant Professor, Department of Pediatric Orthopaedic Surgery, Cincinnati Children's Hospital Medical Center

Shital Parikh, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Medical Association, and Orthopaedic Research Society

Disclosure: Nothing to disclose.

Coauthor(s)

Preeti Batra, MBBS, MD  Staff Physician, Department of Radiology, VS Hospital, India

Disclosure: Nothing to disclose.

Specialty Editor Board

Mininder S Kocher, MD, MPH  Associate Professor of Orthopedic Surgery, Harvard Medical School/Harvard School of Public Health; Associate Director, Division of Sports Medicine, Department of Orthopedic Surgery, Children's Hospital Boston

Mininder S Kocher, MD, MPH is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Association for the History of Medicine, American College of Sports Medicine, American Orthopaedic Society for Sports Medicine, Massachusetts Medical Society, and Pediatric Orthopaedic Society of North America

Disclosure: Smith & Nephew Endoscopy Consulting fee Consulting; EBI Biomet Consulting fee Consulting; OrthoPediatrics Consulting fee Consulting; Pivot Medical Stock Consulting; pediped Consulting fee Consulting; WB Saunders Royalty None; Fixes-4-Kids Consulting

Francisco Talavera, PharmD, PhD  Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

George H Thompson, MD  Director of Pediatric Orthopedic Surgery, Rainbow Babies and Children's Hospital, University Hospitals Case Medical Center, and MetroHealth Medical Center; Professor of Orthopedic Surgery and Pediatrics, Case Western Reserve University School of Medicine

George H Thompson, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Orthopaedic Association, Pediatric Orthopaedic Society of North America, and Scoliosis Research Society

Disclosure: OrthoPediatrics None Consulting; Journal of Pediatric Orthopaedics Salary Management position; SpineForm None Consulting; SICOT None Board membership

Dinesh Patel, MD, FACS  Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital

Dinesh Patel, MD, FACS is a member of the following medical societies: American Academy of Orthopaedic Surgeons

Disclosure: Nothing to disclose.

Chief Editor

Dennis P Grogan, MD  Clinical Professor, Department of Orthopedic Surgery, University of South Florida College of Medicine; Chief of Staff, Department of Orthopedic Surgery, Shriners Hospital for Children of Tampa

Dennis P Grogan, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Medical Association, American Orthopaedic Association, American Orthopaedic Foot and Ankle Society, Eastern Orthopaedic Association, Irish American Orthopaedic Society, Pediatric Orthopaedic Society of North America, and Scoliosis Research Society

Disclosure: Nothing to disclose.

References

  1. Smoker WR, Khanna G. Imaging the craniocervical junction. Childs Nerv Syst. Oct 2008;24(10):1123-45. [Medline].

  2. J. M. Parrot. Les malformations achondrodysplasiques. In: Bulletins de la Société d'anthropologie de Paris, 1878. 1878.

  3. Bailey JA 2nd. Orthopaedic aspects of achondroplasia. J Bone Joint Surg Am. Oct 1970;52(7):1285-301. [Medline].

  4. Nelson MA. Orthopaedic aspects of the chondrodystrophies. The dwarf and his orthopaedic problems. Ann R Coll Surg Engl. Oct 1970;47(4):185-210. [Medline].

  5. Horton WA, Hall JG, Hecht JT. Achondroplasia. Lancet. Jul 14 2007;370(9582):162-72. [Medline].

  6. Laederich MB, Horton WA. Achondroplasia: pathogenesis and implications for future treatment. Curr Opin Pediatr. Aug 2010;22(4):516-23. [Medline].

  7. Wynn J, King TM, Gambello MJ, Waller DK, Hecht JT. Mortality in achondroplasia study: A 42-year follow-up. Am J Med Genet A. Nov 1 2007;143(21):2502-11. [Medline].

  8. Hoover-Fong JE, McGready J, Schulze KJ, Barnes H, Scott CI. Weight for age charts for children with achondroplasia. Am J Med Genet A. Oct 1 2007;143(19):2227-35. [Medline].

  9. Hoover-Fong JE, Schulze KJ, McGready J, Barnes H, Scott CI. Age-appropriate body mass index in children with achondroplasia: interpretation in relation to indexes of height. Am J Clin Nutr. Aug 2008;88(2):364-71. [Medline].

  10. Ireland PJ, McGill J, Zankl A, et al. Functional performance in young Australian children with achondroplasia. Dev Med Child Neurol. Oct 2011;53(10):944-50. [Medline].

  11. Ireland PJ, Johnson S, Donaghey S, Johnston L, Ware RS, Zankl A, et al. Medical management of children with achondroplasia: Evaluation of an Australasian cohort aged 0-5 years. J Paediatr Child Health. Nov 23 2011;[Medline].

  12. Lonstein JE. Treatment of kyphosis and lumbar stenosis in achondroplasia. Basic Life Sci. 1988;48:283-92. [Medline].

  13. Cohen ME, Rosenthal AD, Matson DD. Neurological abnormalities in achondroplastic children. J Pediatr. Sep 1967;71(3):367-76. [Medline].

  14. Modaff P, Horton VK, Pauli RM. Errors in the prenatal diagnosis of children with achondroplasia. Prenat Diagn. Jun 1996;16(6):525-30. [Medline].

  15. Morgan DF, Young RF. Spinal neurological complications of achondroplasia. Results of surgical treatment. J Neurosurg. Apr 1980;52(4):463-72. [Medline].

  16. Erdincler P, Dashti R, Kaynar MY, et al. Hydrocephalus and chronically increased intracranial pressure in achondroplasia. Childs Nerv Syst. Jun 1997;13(6):345-8. [Medline].

  17. Baitner AC, Maurer SG, Gruen MB, Di Cesare PE. The genetic basis of the osteochondrodysplasias. J Pediatr Orthop. Sep-Oct 2000;20(5):594-605. [Medline].

  18. Wang Q, Green RP, Zhao G, Ornitz DM. Differential regulation of endochondral bone growth and joint development by FGFR1 and FGFR3 tyrosine kinase domains. Development. Oct 2001;128(19):3867-76. [Medline].

  19. Carakushansky G, Rosembaum S, Ribeiro MG, et al. Achondroplasia associated with Down syndrome. Am J Med Genet. May 1 1998;77(2):168-9. [Medline].

  20. Lugo N, Becker J, Van Bosse H, et al. Lung volume histograms after computed tomography of the chest with three-dimensional imaging as a method to substantiate successful surgical expansion of the rib cage in achondroplasia. J Pediatr Surg. May 1998;33(5):733-6. [Medline].

  21. Song HR, Choonia AT, Hong SJ, Lee SH, Suh SW, Cha IH. Rotational profile of the lower extremity in achondroplasia: computed tomographic examination of 25 patients. Skeletal Radiol. Dec 2006;35(12):929-34. [Medline].

  22. Jeong ST, Song HR, Keny SM, Telang SS, Suh SW, Hong SJ. MRI study of the lumbar spine in achondroplasia. A morphometric analysis for the evaluation of stenosis of the canal. J Bone Joint Surg Br. Sep 2006;88(9):1192-6. [Medline].

  23. Rollins N, Booth T, Shapiro K. The use of gated cine phase contrast and MR venography in achondroplasia. Childs Nerv Syst. Sep 2000;16(9):569-75; discussion 575-7. [Medline].

  24. Moritani T, Aihara T, Oguma E, Makiyama Y, Nishimoto H, Smoker WR. Magnetic resonance venography of achondroplasia: correlation of venous narrowing at the jugular foramen with hydrocephalus. Clin Imaging. May-Jun 2006;30(3):195-200. [Medline].

  25. Mehta A, Hindmarsh PC. The use of somatropin (recombinant growth hormone) in children of short stature. Paediatr Drugs. 2002;4(1):37-47. [Medline].

  26. Bell DF, Boyer MI, Armstrong PF. The use of the Ilizarov technique in the correction of limb deformities associated with skeletal dysplasia. J Pediatr Orthop. May-Jun 1992;12(3):283-90. [Medline].

  27. Brooks WC, Gross RH. Genu Varum in Children: Diagnosis and Treatment. J Am Acad Orthop Surg. Nov 1995;3(6):326-335. [Medline].

  28. Gil Z, Tauman R, Sivan J, et al. [Neurosurgical aspects in achondroplasia: evaluation and treatment]. Harefuah. Nov 2001;140(11):1026-31, 1118. [Medline].

  29. Kashiwagi N, Suzuki S, Seto Y, Futami T. Bilateral humeral lengthening in achondroplasia. Clin Orthop. Oct 2001;(391):251-7. [Medline].

  30. Mamada K, Nakamura K, Matsushita T, et al. The diameter of callus in leg lengthening: 28 tibial lengthenings in 14 patients with achondroplasia. Acta Orthop Scand. Jun 1998;69(3):306-10. [Medline].

  31. Paley D. Current techniques of limb lengthening. J Pediatr Orthop. Jan-Feb 1988;8(1):73-92. [Medline].

  32. Peretti G, Memeo A, Paronzini A, Marzorati S. Staged lengthening in the prevention of dwarfism in achondroplastic children: a preliminary report. J Pediatr Orthop B. 1995;4(1):58-64. [Medline].

  33. Pyeritz RE, Sack GH Jr, Udvarhelyi GB. Thoracolumbosacral laminectomy in achondroplasia: long-term results in 22 patients. Am J Med Genet. Oct 1987;28(2):433-44. [Medline].

  34. Ravenscroft A, Rout C. Epidural anaesthesia for caesarean section in an achondroplastic dwarf. Br J Anaesth. Feb 1999;82(2):301-3. [Medline].

  35. Lee SH, Modi HN, Song HR, Hazra S, Suh SW, Modi C. Deceleration in maturation of bone during adolescent age in achondroplasia-a retrospective study using RUS scoring system. Skeletal Radiol. Jul 16 2008;[Medline].

  36. Lee ST, Song HR, Mahajan R, Makwana V, Suh SW, Lee SH. Development of genu varum in achondroplasia: relation to fibular overgrowth. J Bone Joint Surg Br. Jan 2007;89(1):57-61. [Medline].

  37. Kim SJ, Agashe MV, Song SH, Choi HJ, Lee H, Song HR. Comparison between upper and lower limb lengthening in patients with achondroplasia: a retrospective study. J Bone Joint Surg Br. Jan 2012;94(1):128-33. [Medline].

  38. Schiedel F, Rödl R. Lower limb lengthening in patients with disproportionate short stature with achondroplasia: a systematic review of the last 20 years. Disabil Rehabil. Nov 23 2011;[Medline].

  39. Koczewski P, Shadi M. [Surgical treatment of short stature of different etiology by the Ilizarov method]. Endokrynol Diabetol Chor Przemiany Materii Wieku Rozw. 2007;13(3):143-6. [Medline].

  40. American Academy of Pediatrics Committee on Genetics. Health supervision for children with achondroplasia. Pediatrics. Mar 1995;95(3):443-51. [Medline].

  41. Frigon VA, Castro FP, Whitecloud TS, Roesch W. Isolated subaxial cervical spine stenosis in achondroplasia. Curr Surg. Jul 1 2000;57(4):354-356. [Medline].

  42. Hunter AG, Bankier A, Rogers JG, et al. Medical complications of achondroplasia: a multicentre patient review. J Med Genet. Sep 1998;35(9):705-12. [Medline].

  43. Mahomed NN, Spellmann M, Goldberg MJ. Functional health status of adults with achondroplasia. Am J Med Genet. Jun 16 1998;78(1):30-5. [Medline].

  44. Mettler G, Fraser FC. Recurrence risk for sibs of children with "sporadic" achondroplasia. Am J Med Genet. Jan 31 2000;90(3):250-1. [Medline].

  45. Thompson NM, Hecht JT, Bohan TP, et al. Neuroanatomic and neuropsychological outcome in school-age children with achondroplasia. Am J Med Genet. Apr 16 1999;88(2):145-53. [Medline].

 
Previous
Next
 
Typical features of a person with achondroplastic dwarfism, including normal trunk with rhizomelic shortening and genu varum.
The characteristic skull seen in patients with achondroplasia, with frontal bossing, small foramen magnum, midface hypoplasia, and relative enlargement of the skull compared to the face.
The progressive narrowing of the coronal interpedicular distance in the lumbar spine in patients with achondroplasia. Note the characteristic shape of the pelvis with horizontal sacral position.
Thoracolumbar kyphosis with narrow lumbar spinal canal and concave posterior bodies in a 13-month-old child with achondroplasia.
Typical features of the lower limbs in a person with achondroplasia, including horizontal acetabular roofs, small sacrosciatic notches, genu varum and ankle varum with relative overgrowth of fibula, and inverted "V" shaped distal femoral physis.
MRI showing cervicomedullary compression at foramen magnum in a patient with achondroplasia.
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2012 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

DISCLAIMER: The content of this Website is not influenced by sponsors. The site is designed primarily for use by qualified physicians and other medical professionals. The information contained herein should NOT be used as a substitute for the advice of an appropriately qualified and licensed physician or other health care provider. The information provided here is for educational and informational purposes only. In no way should it be considered as offering medical advice. Please check with a physician if you suspect you are ill.