Rapadilino syndrome | |
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Other names | Radial and patellar aplasia, Radial and patellar hypoplasia |
Rapadilino syndrome has an autosomal recessive pattern of inheritance. | |
Specialty | Musculoskeletal |
Symptoms | Underdevelopment or absences of the bones in the forearms, thumbs, and kneecaps, cleft pallet or high-arched, palate, diarrhea, and short stature. |
Usual onset | Infancy [1] |
Duration | Lifelong |
Causes | Mutations in the RECQL4 gene [2] |
Frequency | Less than 1,000 known cases in the United States [1] |
RAPADILINO syndrome is an autosomal recessive disorder characterized by: [3]
It is more prevalent in Finland than elsewhere in the world. [4] It has been associated with the gene RECQL4. [4] This is also associated with Rothmund–Thomson syndrome [5] and Baller–Gerold syndrome. [6]
Most people with RAPADILINO syndrome have underdeveloped or absent bones in the forearms and thumbs. Kneecaps may be underdeveloped or absent. Other characteristics include a cleft or high-arched palate, a long, narrow nose, and dislocated joints. [2]
Many infants with RAPADILINO suffer feeding difficulties, as well as diarrhea and vomiting. A combination of poor bone development and nutritional deficiencies can cause slow growth and short stature. [2]
Some RAPADILINO syndrome patients have harmless light brown patches of skin that resemble café-au-lait spots. Patients with RAPADILINO syndrome are more likely to develop osteosarcoma or lymphoma. In those with RAPADILINO syndrome, osteosarcoma typically develops during childhood or adolescence, whereas lymphoma develops in early adulthood. [2]
RAPADILINO syndrome is caused by RECQL4 gene mutations. The RECQL4 gene gives instructions to produce a member of a protein family known as RecQ helicases. Helicases are enzymes that temporarily bind to DNA and unwind the DNA molecule's two spiral strands. This unwinding is needed for DNA replication to prepare for cell division and for mending damaged DNA. The RECQL4 protein is involved in DNA replication and repair as well as the stability of genetic information in cells. [2]
The most frequent RECQL4 gene mutation linked to RAPADILINO syndrome causes the RECQL4 protein to be misassembled. This genetic mutation causes the formation of a protein that lacks exon 7, therefore cannot function as a helicase. In the lack of helicase function, normal DNA replication and repair may be impaired resulting in widespread genetic damage. Although it is unknown how RECQL4 gene mutations produce RAPADILINO syndrome's specific symptoms, these changes may result in the accumulation of DNA errors and cell death. [2]
Werner syndrome (WS) or Werner's syndrome, also known as "adult progeria", is a rare, autosomal recessive disorder which is characterized by the appearance of premature aging.
Helicases are a class of enzymes thought to be vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two hybridized nucleic acid strands, using energy from ATP hydrolysis. There are many helicases, representing the great variety of processes in which strand separation must be catalyzed. Approximately 1% of eukaryotic genes code for helicases.
RecQ helicase is a family of helicase enzymes initially found in Escherichia coli that has been shown to be important in genome maintenance. They function through catalyzing the reaction ATP + H2O → ADP + P and thus driving the unwinding of paired DNA and translocating in the 3' to 5' direction. These enzymes can also drive the reaction NTP + H2O → NDP + P to drive the unwinding of either DNA or RNA.
Bloom syndrome is a rare autosomal recessive genetic disorder characterized by short stature, predisposition to the development of cancer, and genomic instability. BS is caused by mutations in the BLM gene which is a member of the RecQ DNA helicase family. Mutations in genes encoding other members of this family, namely WRN and RECQL4, are associated with the clinical entities Werner syndrome and Rothmund–Thomson syndrome, respectively. More broadly, Bloom syndrome is a member of a class of clinical entities that are characterized by chromosomal instability, genomic instability, or both and by cancer predisposition.
Treacle protein is a protein that studies suggest is involved in the production of a molecule called ribosomal RNA (rRNA) within cells. Treacle is active in the nucleolus, which is a small region inside the nucleus where rRNA is produced. As a major component of cell structures called ribosomes, rRNA is essential for the assembly of proteins. This protein is active during early embryonic development in structures that become bones and other tissues in the face. Although the precise function of this protein is unknown, researchers believe that it plays a critical role in the development of facial bones and related structures.
Interferon regulatory factor 6 also known as IRF6 is a protein that in humans is encoded by the IRF6 gene.
Rothmund–Thomson syndrome (RTS) is a rare autosomal recessive skin condition.
Bloom syndrome protein is a protein that in humans is encoded by the BLM gene and is not expressed in Bloom syndrome.
Protein patched homolog 1 is a protein that is the member of the patched family and in humans is encoded by the PTCH1 gene.
Twinkle protein also known as twinkle mtDNA helicase is a mitochondrial protein that in humans is encoded by the TWNK gene located in the long arm of chromosome 10 (10q24.31).
ATP-dependent DNA helicase Q4 is an enzyme that in humans is encoded by the RECQL4 gene.
The human gene UBR1 encodes the enzyme ubiquitin-protein ligase E3 component n-recognin 1.
PcrA, standing for plasmid copy reduced is a helicase that was originally discovered in a screen for chromosomally encoded genes that are affected in plasmid rolling circle replication in the Gram-positive pathogen Staphylococcus aureus.
Forkhead box protein E1 is a protein that in humans is encoded by the FOXE1 gene.
T-box transcription factor TBX22 is a protein that in humans is encoded by the TBX22 gene.
Warsaw breakage syndrome is a rare genetic condition. Fewer than 10 cases have been reported by 2018. Its clinical manifestations affect several organ systems, and includes microcephaly and severe growth retardation among others.
Genome instability refers to a high frequency of mutations within the genome of a cellular lineage. These mutations can include changes in nucleic acid sequences, chromosomal rearrangements or aneuploidy. Genome instability does occur in bacteria. In multicellular organisms genome instability is central to carcinogenesis, and in humans it is also a factor in some neurodegenerative diseases such as amyotrophic lateral sclerosis or the neuromuscular disease myotonic dystrophy.
Progeroid syndromes (PS) are a group of rare genetic disorders that mimic physiological aging, making affected individuals appear to be older than they are. The term progeroid syndrome does not necessarily imply progeria, which is a specific type of progeroid syndrome.
Baller–Gerold syndrome (BGS) is a rare genetic syndrome that involves premature fusion of the skull bones and malformations of facial, forearm and hand bones. The symptoms of Baller–Gerold syndrome overlap with features of a few other genetics disorders: Rothmund–Thomson syndrome and RAPADILINO syndrome. The prevalence of BGS is unknown, as there have only been a few reported cases, but it is estimated to be less than 1 in a million. The name of the syndrome comes from the researchers Baller and Gerold who discovered the first three cases.
Ischiopatellar dysplasia is a rare autosomal dominant disorder characterized by a hypoplasia of the patellae as well as other bone anomalies, especially concerning the pelvis and feet. It is also known as small patella syndrome, with earlier synonyms being Scott-Taor syndrome, Coxo-podo-patellar syndrome, Patella aplasia, coxa vara, tarsal synostosis, Congenital coxa vara, patella aplasia and tarsal synostosis ischiocoxopodopatellar syndrome.