Dysosteosclerosis

Last updated

Dysosteosclerosis (DSS), also known as autosomal recessive dysosteosclerosis or X-linked recessive dysosteosclerosis, [1] is a rare osteoclast-poor form of osteosclerosis that is presented during infancy and early childhood, characterized by progressive osteosclerosis and platyspondyly. [2] [3] Platyspondyly and other skeletal abnormalities are radiographic features of the disease which distinguish DSS from other osteosclerotic disorders. Patients usually experience neurological and psychological deterioration, therefore patients are commonly associated with delayed milestones.

Contents

The cause of DSS is unclear. Different genetic mutations are observed in patients, therefore it is suggested that the cause is genetically heterogeneous. Genetic mutations responsible include, but are not limited to, TCIRG1, TNFRSF11A , and SLC29A3. It is congenital and inherited as an autosomal recessive disorder, however, an X-linked recessive inheritance is outlined in some families. [4] There is no cure for DSS. Supportive care includes orthopaedic care. Symptomatic treatment involves the reduction in calcium intake in diet. [5] Less than 30 cases of DSS have been reported in literature to date. [6]

Symptoms and Signs

The main signs and symptoms of DSS includes: [1] [7]

  1. Skeletal abnormalities: platyspondyly, sclerosis
  2. Physical abnormalities: short stature, macrocephaly
  3. Neurological abnormalities: delayed development, mental retardation

Skeletal abnormalities

In general, patients with DSS develop osteopenia and bone fragility. DSS also affects specific areas of the human skeleton, such as the spine, skull, pelvis, and limbs.

The most common sign of DSS is platyspondyly, which is the flattening of vertebral bodies of the axial skeleton, present in 80-99% of individuals with DSS. Other spinal abnormalities associated with DSS include widened intervertebral disks, small, dense vertebral bodies, irregular vertebral endplates, hypoplastic vertebral bodies, and pronounced vertebral anterior notches. [6] [7]

More than 80% of patients also reported abnormalities of the skull. Common symptoms include craniofacial hyperostosis, which is the excessive growth of bone in the skull and face. Skull base sclerosis, periorbital sclerosis, hypoplastic mandibular condyle, and absent paranasal or frontal sinuses are present in rare cases. [6] [7]

It is also reported that individuals may also have pelvic abnormalities. This includes the development of narrow iliac wings, as well as widened femoral necks. However, incidence of both symptoms are rare in patients with DSS, occurring in less than 30% of cases. [6] [7]

The occurrence of DSS also leads to deformities of the limbs. 80% of patients reported with abnormalities of the metaphysis such as metaphyseal flaring, radiolucent metaphyses, abnormal metaphyseal trabeculation, which is abnormal trabecula patterns in the metaphyseal region, and epimetaphyseal sclerosis. Other limbic abnormalities include progressive bowing of long bones, which is present in rare cases. [6] [7]

Physical abnormalities

In general, patients appear to be short statured. In addition, as a result of sclerosis of the frontal and parietal region of the calvarium, [8] macrocephaly and square shaped heads are reported in more than 80% of patients. [1] [4]

Abnormal skin conditions of red-violet macular mottled skins over the entire body are occasionally observed in patients. However it is unclear whether this clinical feature is relevant to diagnosis of DSS. [7] [9]

Neurological abnormalities

Visual problems are often found in people with DSS. Patients experience optic atrophy due to progressive cranial nerve compression, which may lead to nystagmus or even blindness in severe cases. [4] [10]

Other neurological abnormalities include intellectual disability, speech and psychological deterioration. Convulsions and status epilepticus are also present in patients, however the mechanisms for the development of these features are unknown. [4] Patients also experience cranial nerve damage resulting from progressive cranial pressure. [4] [9]

Pathogenesis

Cytogenetic location of TCIRG1 Location of TCIRG1.png
Cytogenetic location of TCIRG1

DSS is classified as an autosomal recessive disease(OMIM 224300), but it is also identified as an X-linked recessive inheritance in certain families. [4] The total number of genes that are responsible for causing the disease and the correlation between genotype and phenotype remains unclear. Multiple gene mutations were identified in different patients via whole genome sequencing, therefore it is presumed that DSS is genetically heterogeneous.

TCIRG1 mutation

The TCIRG1 gene is present in chromosome locus 11q13, which encodes for the a3 subunit of vacuolar H+ ATPase (V-ATPase) that is unique to osteoclasts. [12] The a3 subunit is responsible in anchoring the vacuolar proton pump to the ruffled membrane of osteoclasts. [9] The V-ATPase is important in mediating the transport of hydrogen ions into the resorption lacunae, which is a pit on the bone surface enclosed by the osteoclast for bone resorption. The accumulation of ions in the lacuna facilitates the decomposition of hydroxyapatite crystals by creating an acidic environment, resulting in bone resorption. [12]

Cytogenetic location of TNFRSF11A TNFRSF11A location.png
Cytogenetic location of TNFRSF11A

Mutation of the gene results in osteoclast-rich osteopetrosis due to poor translation and altered structure of proton pump structure, which is normally involved in large amounts of osteoclast activity leading to absorption of bone tissue. [12] Mutation of TCIRG1 gene may arise from deletion or gene splicing defects, leading to frame-shifts of the nucleotides of the gene. [12]

TCIRG1 mutations illustrate the heterogeneity of DSS through a case study where DSS occurred due to a frameshift mutation, in conjunction with a mutation at an intron located in the gene in one of the alleles of chromosome 11 resulting in a splice site mutation. [9] Despite a frameshift mutation altering the C-terminal of the proton pump, due to increased remnant expression of the wild type transcript, it only resulted in intermediate autosomal recessive DSS due to the partial retainment of vacuolar proton pump function. [9]

TNFRSF11A mutation

The TNFRSF11A gene is present in chromosome locus 18q21.33, which encodes for the receptor activator of NF-κB (RANK). [13] RANK is expressed in immature osteoclasts, which facilitates osteoclasts maturation upon binding of RANK ligand (RANKL). Binding of RANK ligand mediates the RANK/RANKL/OPG signalling pathway. The pathway mediates osteoclast differentiation and activation by promoting differentiation of precursors into multinucleated osteoclasts, and activating osteoclasts, thereby contributing to bone resorption and remodelling. Health conditions related to genetic changes in TNFRSF11A includes osteopetrosis, osteolysis, and Paget's disease of bone. [14] [15]

Multiple reports of gene mutations exists underlining the mutation of the exons and introns leading to aberrant splicing. There are five variants to the TNFRSF11A gene which produces five unique protein iso-forms. The effects of alternative splicing on each variants are unclear. However, it is suggested that such changes lead to different expression patterns of the gene in both space and time. Some mutant splicing variants would undergo nonsense-mediated mRNA decay (NMD), while others would not be subjected to NMD, and instead produce a truncated isoform of the RANK protein. The mutated protein has structural defects hence hinders normal function in the signalling pathway, contributing to development of the disease. [14] [15]

Cytogenetic location of SLC29A3 Cytogenetic location of SLC29A3.png
Cytogenetic location of SLC29A3

SLC29A3 mutation

The SLC29A3 gene is present in chromosome locus10q22.1, which encodes for the equilibrative nucleoside transporter 3 (ENT3), a nucleoside transporter that is present in membranes of mitochondria and lysosomes. [9] ENT3 is responsible for the trafficking of nucleoside, free purines and pyrimidines into the mitochondria and out of lysosomes. [9] [16] Mutations in the gene is often accompanied by histiocytosis-lymphadenopathy plus syndrome, which is characterised by the accumulation of histiocytes leading to lymphadenopathy and other symptoms. [16]

Insertion in the coding region was reported in a patient but no records were found in any genetic databanks. Missense mutation was reported to be present in multiple patients and ranked disease-causing by MutationTaster. [9] This insertion mutation is located in the loop within transmembrane helices 1 and 2, while the missense mutations is located in the loop within transmembrane helix 6, 9, and 11. [17]

Mutation leads to impaired ENT3 transportation activity, accumulation of nucleotides and nucleoside in lysosomes. [9] As osteoclasts express the SLC29A3 gene, mutation results in incapacitated differentiated osteoclasts' ability in demineralising calcium phosphate crystal surfaces, disrupted osteoclastic differentiation, and diminished osteoclast counts. [17] The reduced osteoclast differentiation and activity results in decreased demineralisation and reabsorption of bone structures.

Diagnosis

Medical diagnosis of DSS involves various examinations and evaluations. This usually includes physical examinations, medical history evaluations, assessment of signs and symptoms, laboratory tests and image studies. Biopsy may also be required if necessary. [1] [17]

Signs and symptoms of DSS show similarities with multifarious disorders and diseases such as osteosclerosis, H syndrome and Pyle disease. [1] [17] As such, it is likely that DSS is consequently incorrectly identified as osteopetrosis. [4] Therefore, additional tests may be performed in order to arrive at a definitive diagnosis. [1] [17]

Radiographic features

Whilst some symptoms of DSS can be visually identified, many key symptoms of DSS cannot be identified as such. Therefore, radiographic techniques are required to reach a correct diagnosis for DSS.

Abnormal features of the axial skeleton

Skull

In the skull, sclerosis is predominantly observed in the cranial vault and skull base. [10] Other symptoms displayed in the skull include dental anomalies such as abnormal dentition, hypodontia and impaired tooth calcification; [9] intracranial calcifications, which is the calcification of the brain parenchyma; narrow optic canal and other cranial foramina. [18]

Abnormal features of the appendicular skeleton

A frontal radiograph showing metaphyseal flaring of both femora Erlenmeyer-flask-deformity.jpg
A frontal radiograph showing metaphyseal flaring of both femora
Chest

The ribs are sclerotic, truncated, expanded, and featureless. Sclerosis is also present in the sternum, clavicles and scapulae. Pectus carinatum, a chest deformity, is also characteristic of the disease. [18]

Long bones

Sclerosis of epiphyses, diaphyses, and metaphyses with increased radiolucency are key characteristics of the disease. [18] In addition, mottled metaphyseal sclerosis and widening are also present in patients. [4] [9] Development of irregular patchy sclerosis along the bone can also be identified, [9] as well as metaphyseal flaring evolve towards Erlenmeyer flask deformity with nonuniform patches of sclerosis, which are especially prevalent in older patients. [10]

The metadiaphyses, a portmanteau of the metaphysis and diaphysis, [20] are bulbous and expanded with bowing and relative radiolucency. The expanded regions are also sclerotic and gives the characteristic bone-in-bone appearance. [4]

Spine

Platyspondyly is the development of flattened vertebral bodies, which is one of the most notable symptoms as it distinguishes DSS from other similar diseases such as osteosclerosis. It is observed to be most significant in the thoracic region with increased intervertebral spaces. [4] Platyspondyly development begins with generalised osteosclerosis, then subsequent interspersing sclerotic bands develop within vertebral bodies with normal bone density, showing radiolucency. [18]

Management

Overall the disease has a poor prognosis, with treatment mainly focusing on palliation and comfort care. [2]

As the mechanism and clinical course of DSS remains unclear, definitive treatment is not available for patients. Bone marrow transplant may improve skeletal abnormalities, however it is improbable the transplant will ameliorate the unexplained neurological deteriorations. [4] In addition, the surgery may not be suitable for every patients as the underlying genetic cause of the disease varies amongst patients. Advice of control and reduction in excessive calcium intake may be recommended by physicians to ensure circulating levels of parathyroid hormones are normal to induce and maintain bone resorption. [5]

Related Research Articles

<span class="mw-page-title-main">Macrocephaly</span> Abnormally large head size

Macrocephaly is a condition in which circumference of the human head is abnormally large. It may be pathological or harmless, and can be a familial genetic characteristic. People diagnosed with macrocephaly will receive further medical tests to determine whether the syndrome is accompanied by particular disorders. Those with benign or familial macrocephaly are considered to have megalencephaly.

<span class="mw-page-title-main">Osteopetrosis</span> Rare disease of the bones

Osteopetrosis, literally 'stone bone', also known as marble bone disease or Albers-Schönberg disease, is an extremely rare inherited disorder whereby the bones harden, becoming denser, in contrast to more prevalent conditions like osteoporosis, in which the bones become less dense and more brittle, or osteomalacia, in which the bones soften. Osteopetrosis can cause bones to dissolve and break.

<span class="mw-page-title-main">Waardenburg syndrome</span> Genetic condition involving hearing loss and depigmentation

Waardenburg syndrome is a group of rare genetic conditions characterised by at least some degree of congenital hearing loss and pigmentation deficiencies, which can include bright blue eyes, a white forelock or patches of light skin. These basic features constitute type 2 of the condition; in type 1, there is also a wider gap between the inner corners of the eyes called telecanthus, or dystopia canthorum. In type 3, which is rare, the arms and hands are also malformed, with permanent finger contractures or fused fingers, while in type 4, the person also has Hirschsprung's disease. There also exist at least two types that can result in central nervous system (CNS) symptoms such as developmental delay and muscle tone abnormalities.

Kniest dysplasia is a rare form of dwarfism caused by a mutation in the COL2A1 gene on chromosome 12. The COL2A1 gene is responsible for producing type II collagen. The mutation of COL2A1 gene leads to abnormal skeletal growth and problems with hearing and vision. What characterizes Kniest dysplasia from other type II osteochondrodysplasia is the level of severity and the dumb-bell shape of shortened long tubular bones.

<span class="mw-page-title-main">V-ATPase</span> Family of transport protein complexes

Vacuolar-type ATPase (V-ATPase) is a highly conserved evolutionarily ancient enzyme with remarkably diverse functions in eukaryotic organisms. V-ATPases acidify a wide array of intracellular organelles and pumps protons across the plasma membranes of numerous cell types. V-ATPases couple the energy of ATP hydrolysis to proton transport across intracellular and plasma membranes of eukaryotic cells. It is generally seen as the polar opposite of ATP synthase because ATP synthase is a proton channel that uses the energy from a proton gradient to produce ATP. V-ATPase however, is a proton pump that uses the energy from ATP hydrolysis to produce a proton gradient.

<span class="mw-page-title-main">Hajdu–Cheney syndrome</span> Medical condition

Hajdu–Cheney syndrome, also called acroosteolysis with osteoporosis and changes in skull and mandible, arthrodentoosteodysplasia and Cheney syndrome, is an extremely rare autosomal dominant congenital disorder of the connective tissue characterized by severe and excessive bone resorption leading to osteoporosis and a wide range of other possible symptoms. Mutations in the NOTCH2 gene, identified in 2011, cause HCS. HCS is so rare that only about 50 cases have been reported worldwide since the discovery of the syndrome in 1948

<span class="mw-page-title-main">Robinow syndrome</span> Rare genetic disorder characterized by a fetal face

Robinow syndrome is an extremely rare genetic disorder characterized by short-limbed dwarfism, abnormalities in the head, face, and external genitalia, as well as vertebral segmentation. The disorder was first described in 1969 by human geneticist Meinhard Robinow, along with physicians Frederic N. Silverman and Hugo D. Smith, in the American Journal of Diseases of Children. By 2002, over 100 cases had been documented and introduced into medical literature.

An osteochondrodysplasia, or skeletal dysplasia, is a disorder of the development of bone and cartilage. Osteochondrodysplasias are rare diseases. About 1 in 5,000 babies are born with some type of skeletal dysplasia. Nonetheless, if taken collectively, genetic skeletal dysplasias or osteochondrodysplasias comprise a recognizable group of genetically determined disorders with generalized skeletal affection. These disorders lead to disproportionate short stature and bone abnormalities, particularly in the arms, legs, and spine. Skeletal dysplasia can result in marked functional limitation and even mortality.

<span class="mw-page-title-main">Pseudoachondroplasia</span> Inherited disorder of bone growth

Pseudoachondroplasia is an inherited disorder of bone growth. It is a genetic autosomal dominant disorder. It is generally not discovered until 2–3 years of age, since growth is normal at first. Pseudoachondroplasia is usually first detected by a drop of linear growth in contrast to peers, a waddling gait or arising lower limb deformities.

Metaphyseal dysplasia, or Pyle disease, is a disorder of the bones. It is a rare disease in which the outer part of the shafts of long bones is thinner than normal and there is an increased chance of fractures. Its hallmark feature is an abnormality of the long bones in the arms and legs in which the ends (metaphyses) of the bones are abnormally broad; the shape of the bones resembles a boat oar or paddle. The broad metaphyses are due to enlargement of the spongy inner layer of bone. Although trabecular bone is expanded, the dense outermost layer of bone is thinner than normal. As a result, the bones are fragile and fracture easily. The bone abnormalities in the legs commonly cause knock knees in affected individuals.

<span class="mw-page-title-main">Pycnodysostosis</span> Metabolic disorder leading to high bone density and malformation

Pycnodysostosis is a lysosomal storage disease of the bone caused by a mutation in the gene that codes the enzyme cathepsin K. It is also known as PKND and PYCD.

<span class="mw-page-title-main">Gerodermia osteodysplastica</span> Medical condition

Gerodermia osteodysplastica (GO) is a rare autosomal recessive connective tissue disorder included in the spectrum of cutis laxa syndromes.

Wrinkly skin syndrome(WSS) is a rare genetic condition characterized by sagging, wrinkled skin, low skin elasticity, and delayed fontanelle (soft spot) closure, along with a range of other symptoms. The disorder exhibits an autosomal recessive inheritance pattern with mutations in the ATP6V0A2 gene, leading to abnormal glycosylation events. There are only about 30 known cases of WSS as of 2010. Given its rarity and symptom overlap with other dermatological conditions, reaching an accurate diagnosis is difficult and requires specialized dermatological testing. Limited treatment options are available but long-term prognosis is variable from patient to patient, based on individual case studies. Some skin symptoms recede with increasing age, while progressive neurological advancement of the disorder causes seizures and mental deterioration later in life for some patients.

<span class="mw-page-title-main">Cranio-lenticulo-sutural dysplasia</span> Medical condition

Cranio-lenticulo-sutural dysplasia is a neonatal/infancy disease caused by a disorder in the 14th chromosome. It is an autosomal recessive disorder, meaning that both recessive genes must be inherited from each parent in order for the disease to manifest itself. The disease causes a significant dilation of the endoplasmic reticulum in fibroblasts of the host with CLSD. Due to the distension of the endoplasmic reticulum, export of proteins from the cell is disrupted.

<span class="mw-page-title-main">Ghosal hematodiaphyseal dysplasia</span> Medical condition

Ghosal hematodiaphyseal dysplasia, is a rare, autosomal recessive disease, characterized by diaphyseal dysplasia and metaphyseal dysplasia of the long bones and refractory anemia.

Sclerosteosis is an autosomal recessive disorder characterized by bone overgrowth. It was first described in 1958 but given the current name in 1967. Excessive bone formation is most prominent in the skull, mandible and tubular bones. It can cause facial distortion and syndactyly. Increased intracranial pressure can cause sudden death in patients. It is a rare disorder that is most prominent in the Afrikaner population in South Africa, but there have also been cases of American and Brazilian families.

<span class="mw-page-title-main">Tricho–dento–osseous syndrome</span> Medical condition

Tricho–dento–osseous syndrome (TDO) is a rare, systemic, autosomal dominant genetic disorder that causes defects in hair, teeth, and bones respectively. This disease is present at birth. TDO has been shown to occur in areas of close geographic proximity and within families; most recent documented cases are in Virginia, Tennessee, and North Carolina. The cause of this disease is a mutation in the DLX3 gene, which controls hair follicle differentiation and induction of bone formation. All patients with TDO have two co-existing conditions called enamel hypoplasia and taurodontism in which the abnormal growth patterns of the teeth result in severe external and internal defects. The hair defects are characterized as being rough, course, with profuse shedding. Hair is curly and kinky at infancy but later straightens. Dental defects are characterized by dark-yellow/brownish colored teeth, thin and/or possibly pitted enamel, that is malformed. The teeth can also look normal in color, but also have a physical impression of extreme fragility and thinness in appearance. Additionally, severe underbites where the top and bottom teeth fail to correctly align may be present; it is common for the affected individual to have a larger, more pronounced lower jaw and longer bones. The physical deformities that TDO causes become more noticeable with age, and emotional support for the family as well as the affected individual is frequently recommended. Adequate treatment for TDO is a team based approach, mostly involving physical therapists, dentists, and oromaxillofacial surgeons. Genetic counseling is also recommended.

<span class="mw-page-title-main">Craniometaphyseal dysplasia</span> Medical condition

Craniometaphyseal dysplasia is a rare skeletal disorder that results from a mutation in the ANKH or GJA1 genes. The condition is characterized abnormal facial features, impairment of cranial nerves, and malformation of the long bones in the limbs.

<span class="mw-page-title-main">Malignant infantile osteopetrosis</span> Human disease

Malignant infantile osteopetrosis is a rare osteosclerosing type of skeletal dysplasia that typically presents in infancy and is characterized by a unique radiographic appearance of generalized hyperostosis.

<span class="mw-page-title-main">Spondyloenchondrodysplasia</span> Medical condition

Spondyloenchondrodysplasia is the medical term for a rare spectrum of symptoms that are inherited following an autosomal recessive inheritance pattern. Skeletal anomalies are the usual symptoms of the disorder, although its phenotypical nature is highly variable among patients with the condition, including symptoms such as muscle spasticity or thrombocytopenia purpura. It is a type of immunoosseous dysplasia.

References

  1. 1 2 3 4 5 6 "Dysosteosclerosis". Dovemed.
  2. 1 2 "Orphanet: Dysosteosclerosis". www.orpha.net.
  3. Penna S, Capo V, Palagano E, Sobacchi C, Villa A (2019-02-19). "One Disease, Many Genes: Implications for the Treatment of Osteopetroses". Frontiers in Endocrinology. 10: 85. doi: 10.3389/fendo.2019.00085 . PMC   6389615 . PMID   30837952.
  4. 1 2 3 4 5 6 7 8 9 10 11 Elçioglu NH, Vellodi A, Hall CM (August 2002). "Dysosteosclerosis: a report of three new cases and evolution of the radiological findings". Journal of Medical Genetics. 39 (8): 603–7. doi:10.1136/jmg.39.8.603. PMC   1735202 . PMID   12161605.
  5. 1 2 Whyte MP, Wenkert D, McAlister WH, Novack DV, Nenninger AR, Zhang X, et al. (November 2010). "Dysosteosclerosis presents as an "osteoclast-poor" form of osteopetrosis: comprehensive investigation of a 3-year-old girl and literature review". Journal of Bone and Mineral Research. 25 (11): 2527–39. doi:10.1002/jbmr.131. PMC   3179286 . PMID   20499338.
  6. 1 2 3 4 5 "Dysosteosclerosis". Genetic and Rare Diseases Information Center. National Institutes of Health.
  7. 1 2 3 4 5 6 Przylepa KA. "DYSOSTEOSCLEROSIS". omim.org.
  8. Beighton P, Cremin BJ (6 December 2012). Sclerosing Bone Dysplasias. Springer London. pp. 95–100. ISBN   978-1-4471-1292-1.
  9. 1 2 3 4 5 6 7 8 9 10 11 12 Howaldt A, Nampoothiri S, Quell LM, Ozden A, Fischer-Zirnsak B, Collet C, et al. (March 2019). "Sclerosing bone dysplasias with hallmarks of dysosteosclerosis in four patients carrying mutations in SLC29A3 and TCIRG1". Bone. 120: 495–503. doi:10.1016/j.bone.2018.12.002. PMID   30537558. S2CID   54469878.
  10. 1 2 3 John E, Kozlowski K, Masel J, Muralinath S, Vijayalakshmi G (August 1996). "Dysosteosclerosis". Australasian Radiology. 40 (3): 345–7. doi:10.1111/j.1440-1673.1996.tb00417.x. PMID   8826749.
  11. "TCIRG1 gene". Genetics Home Reference. Retrieved 2020-04-08.
  12. 1 2 3 4 Frattini A, Orchard PJ, Sobacchi C, Giliani S, Abinun M, Mattsson JP, et al. (July 2000). "Defects in TCIRG1 subunit of the vacuolar proton pump are responsible for a subset of human autosomal recessive osteopetrosis". Nature Genetics. 25 (3): 343–6. doi:10.1038/77131. PMID   10888887. S2CID   21316081.
  13. 1 2 "TNFRSF11A gene". Genetics Home Reference. Retrieved 2020-04-04.
  14. 1 2 Guo L, Elcioglu NH, Karalar OK, Topkar MO, Wang Z, Sakamoto Y, et al. (June 2018). "Dysosteosclerosis is also caused by TNFRSF11A mutation". Journal of Human Genetics. 63 (6): 769–774. doi:10.1038/s10038-018-0447-6. PMID   29568001. S2CID   4133369.
  15. 1 2 Xue JY, Wang Z, Shinagawa S, Ohashi H, Otomo N, Elcioglu NH, et al. (October 2019). "TNFRSF11A-Associated Dysosteosclerosis: A Report of the Second Case and Characterization of the Phenotypic Spectrum". Journal of Bone and Mineral Research. 34 (10): 1873–1879. doi: 10.1002/jbmr.3805 . PMID   31163101. S2CID   174813504.
  16. 1 2 3 "SLC29A3 gene". Genetics Home Reference. National Institutes of Health.
  17. 1 2 3 4 5 Campeau PM, Lu JT, Sule G, Jiang MM, Bae Y, Madan S, et al. (November 2012). "Whole-exome sequencing identifies mutations in the nucleoside transporter gene SLC29A3 in dysosteosclerosis, a form of osteopetrosis". Human Molecular Genetics. 21 (22): 4904–9. doi:10.1093/hmg/dds326. PMC   3607481 . PMID   22875837.
  18. 1 2 3 4 Castriota Scanderbeg A (26 October 2005). Abnormal Skeletal Phenotypes: From Simple Signs to Complex Diagnoses. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 690–691. ISBN   9783540679974.
  19. Nasman A. "Erlenmeyer flask deformity | Radiology Case | Radiopaedia.org". Radiopaedia. Retrieved 2020-04-19.
  20. Hacking C, Bell DJ. "Metadiaphysis". Radiopaedia.