Alazami syndrome explained

Alazami syndrome is a rare autosomal recessive genetic disorder characterized by short stature, severe mental retardation, speech delay, skeletal deformities, intellectual disability, and distinctive facial features (facial dysmorphisms). Facial features include underdevelopment of the cheekbones, deep-set eyes, broad nose and an enlargement at the corners of the mouth (macrostomia). Skeletal deformities include scoliosis and mild epiphyseal changes in the first bones of the fingers (proximal phalanges), but no severe hip dislocation.[1] [2] It was first described by Alazami et al in 2012. The syndrome was presented by a Saudi Arabian family with primordial dwarfism syndrome with LARP7 gene variations.[3] Some affected patients show the lack of voluntary coordination of muscle movements (Ataxia), manifested as a clumsy walking pattern, with frequent trips or falls.[4]

Causes

The genetic cause of the syndrome is the deletion of LARP7 gene (La Ribonucleoprotein 7)[5] located on chromosome 4q25. The gene expresses a small nuclear ribonucleoprotein that hinders a transcription factor required for resuming transcription by RNA polymerase II enzyme.[6] LARP7 loss-of-function mutations in humans suffer from primordial dwarfism, intellectual disabilities, and facial characteristics changes. Several Alazami syndrome patients show a reduced telomerase activity and very short lymphocyte telomeres.[7] Eventhough thyroid cancer is rare among children and adolescents, those with this disease are LARP7 variants and have Alazami syndrome and tumor susceptibility.[8]

Notes and References

  1. Alazami syndrome due to LARP7 gene mutation: Expanding the phenotype. A.. Bajafar. F.. Rifai. Y.. Al-Said. E.. Cupler. October 15, 2019. Journal of the Neurological Sciences. 405. 272–273. www.jns-journal.com. 10.1016/j.jns.2019.10.1326. 209478208 .
  2. https://www.malacards.org/card/alazami_syndrome
  3. Updating the neurodevelopmental profile of Alazami syndrome: illustrating the role of developmental assessment in rare genetic disorders - PMC. 2019 . 6663627 . Wojcik . M. H. . Linnea . K. . Stoler . J. M. . Rappaport . L. . American Journal of Medical Genetics. Part A . 179 . 8 . 1565–1569 . 10.1002/ajmg.a.61189 . 31074943 .
  4. https://www.rarechromo.org/media/singlegeneinfo/Single%20Gene%20Disorder%20Guides/Alazami%20Syndrome%20QFN.pdf
  5. Web site: Alazami Syndrome - CAGS. cags.org.ae.
  6. Alazami syndrome: Report of three Indian patients with phenotypic spectrum from adolescence to adulthood. Sweta. Das. Koumudi. Godbole. Suneetha Susan Cleave. Abraham. Paramasivam. Ganesan. Payal. Kamdar. Sumita. Danda. May 8, 2021. American Journal of Medical Genetics. Part A. 185. 5. 1606–1609. PubMed. 10.1002/ajmg.a.62118. 33569879. 231883626 .
  7. The Alazami Syndrome-Associated Protein LARP7 Guides U6 Small Nuclear RNA Modification and Contributes to Splicing Robustness. Daniele. Hasler. Rajyalakshmi. Meduri. Maciej. Bąk. Gerhard. Lehmann. Leonhard. Heizinger. Xin. Wang. Zhi-Tong. Li. François M.. Sement. Astrid. Bruckmann. Anne-Catherine. Dock-Bregeon. Rainer. Merkl. Reinhard. Kalb. Eva. Grauer. Erdmute. Kunstmann. Mihaela. Zavolan. Mo-Fang. Liu. Utz. Fischer. Gunter. Meister. March 5, 2020. Molecular Cell. 77. 5. 1014–1031.e13. 10.1016/j.molcel.2020.01.001. 32017898 . 211035370 . free.
  8. Alazami syndrome: the first case of papillary thyroid carcinoma. Ivan. Ivanovski. Stefano Giuseppe. Caraffi. Elisa. Magnani. Simonetta. Rosato. Marzia. Pollazzon. Leslie. Matalonga. Simonetta. Piana. Davide. Nicoli. Chiara. Baldo. Sergio. Bernasconi. Andrea. Frasoldati. Orsetta. Zuffardi. Livia. Garavelli. February 8, 2020. Journal of Human Genetics. 65. 2. 133–141. www.nature.com. 10.1038/s10038-019-0682-5. 31656314 . 254110136 .

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