الكروموسوم 5، هوواحد من 23 زوج من الكروموسومات البشرية. عادة ما يمتلك البشر زوجان من هذا الكروموسوم. يحتوي الكروموسومخمسة على 181 مليون زوج قاعدي (مادة بناء الدنا) ويمثل حوالي 6% من إجمالي الدنا في الخلايا. الكروموسوم 5 من أكبر الكروموسومات البشرية، حتى الآن هوأحد أقل الكروموسات كثافة بالجينات. يتمثل ذلك بعدد من المناطق ذات الجينات القليلة والتي تظهر بصورة كبيرة في الحفظ الجيني الغير مرمز للفقاريات الغير ثديية، مما يشير على أنها مقيدة وظيفياً.

نظراً لاختلاف المناهج التي يستخدمها الباحثون في التنبؤ بعدد الجينات في جميع كروموسوم، هناك تباين في أعداد الجينات المقدرة. من الأرجح حتى الكروموسومخمسة يحتوي على 900-1.300 جين.

الكروموسومخمسة مسئول عن الكثير من أشكال نمووتطور (تقسيمات الخلية) التغيرات المسببة للسرطان، ومن أمثلتها ابيضاض الدم النقوي الحاد.

الجينات

القائمة التالية للجينات الواقعة على الكروموسوم 5:

• ADAMTS2: ADAM metallopeptidase with thrombospondin type 1 motif, 2
• APC: adenomatosis polyposis coli
• CAST: Calpastatin
• EGR1: early growth response protein 1
• ERAP1: endoplasmic reticulum aminopeptidase 1 (previously called ARTS-1)
• ERAP2: endoplasmic reticulum aminopeptidase 2
• DTDST: diastrophic dysplasia sulfate transporter
• ERCC8: excision repair cross-complementing rodent repair deficiency, complementation group 8
• FGFR4: fibroblast growth factor receptor 4
• GM2A: GM2 ganglioside activator
• HEXB: hexosaminidase B (beta polypeptide)
• MASS1: monogenic, audiogenic seizure susceptibility 1 homolog (mouse)
• MCCC2: methylcrotonoyl-Coenzyme A carboxylase 2 (beta)
• MEF2C: Myocyte-specific enhancer factor 2C
• MTRR: 5-methyltetrahydrofolate-homocysteine methyltransferase reductase
• NIPBL: Nipped-B homolog (Drosophila)
• NSD1: Transcription coregulator protein
• Pikachurin: Responsible for the functioning of the ribbon synapses; allows the eye to track moving objects
• SLC22A5: solute carrier family 22 (organic cation transporter), member 5
• SLC26A2: solute carrier family 26 (sulfate transporter), member 2
• SMN1: survival motor neuron 1, telomeric
• SMN2: survival motor neuron 2, centromeric
• SNCAIP: synuclein, alpha interacting protein (synphilin)
• SPINK5: serine protease inhibitor Kazal-typeخمسة (LEKTI)
• SPINK6: serine protease inhibitor Kazal-type 6
• SPINK9: serine protease inhibitor Kazal-typeتسعة (LEKTI-2)
• TCOF1: Treacher Collins-Franceschetti syndrome 1
• TGFBI: keratoepithelin
• TTC37: Tetratricopeptide repeat domain 37
• FGF1: fibroblast growth factor 1 (acidic fibroblast growth factor)

الأمراض والاضطرابات

القائمة التالية للأمراض المرتبطة بالجينات الواقعة على الكروموسوم 5:

• عدم تخلق الغضاريف النوع 1ب
• عدم تخلق الغضاريف النوع 2
• متلازمة الكوكايين
• متلازمة كورلانيا ده لانج
• Corneal dystrophy of Bowman layer, type I
• Corneal dystrophy of Bowman layer, type II
• Cri du Chat
• Diastrophic dysplasia
• Ehlers-Danlos syndrome
• Ehlers-Danlos syndrome, dermatosparaxis type
• Familial adenomatous polyposis
• Granular corneal dystrophy type I
• Granular corneal dystrophy type II
• GM2-gangliosidosis, AB variant
• Homocystinuria
• 3-Methylcrotonyl-CoA carboxylase deficiency
• متلازمة خلل التنسج النقوي
• متلازمة نثرتون
• الاحتياج للنيكوتين
• سقم پاركنسن
• Primary carnitine deficiency
• Recessive multiple epiphyseal dysplasia
• سقم ساندهوف
• Spinal muscular atrophy
• Sotos Syndrome
• Survival motor neuron spinal muscular atrophy
• Tمتلازمة تريتشر كولينز
• Tricho-hepato-enteric syndrome
• متلازمة آشر
• متلازمة آشر النوع 2

الحالات السقمية الكروموسومية

القائمة التالية للحالات السقمية التي تنتج عن تغيرات في بنية أوعدد نسخ الكروموسوم 5:

• Cri-du-chat syndrome is caused by a deletion of the end of the short (p) arm of chromosome 5. This chromosomal change is written as 5p-. The signs and symptoms of cri-du-chat syndrome are probably related to the loss of multiple genes in this region. Researchers have not identified all of these genes or determined how their loss leads to the features of the disorder. They have discovered, however, that a larger deletion tends to result in more severe mental retardation and developmental delays in people with cri-du-chat syndrome.

Researchers have defined narrow regions of the short arm of chromosomeخمسة that are associated with particular features of cri-du-chat syndrome. A specific region designated 5p15.3 is associated with a cat-like cry, and a nearby region called 5p15.2 is associated with mental retardation, small head (microcephaly), and distinctive facial features.

• Familial Adenomatous Polyposis is caused by a deletion of the APC tumor suppressor gene on the long (q) arm of chromosome 5. This chromosomal change results in thousands of colonic polyps which gives the patient a 100% risk of colon cancer if total colectomy is not done.

• Chromosome 5q deletion syndrome is caused by the deletion of the q arm (long arm) of chromosome 5. This deletion has been linked to several blood related disorders including Myelodysplastic syndrome and erythroblastopenia. This is a different condition then Cri-du-chat which was mentioned above.

• Other changes in the number or structure of chromosomeخمسة can have a variety of effects, including delayed growth and development, distinctive facial features, birth defects, and other medical problems. Changes to chromosomeخمسة include an extra segment of the short (p) or long (q) arm of the chromosome in each cell (partial trisomy 5p or 5q), a missing segment of the long arm of the chromosome in each cell (partial monosomy 5q), and a circular structure called ring chromosome 5. A ring chromosome occurs when both ends of a broken chromosome are reunited.

المصادر

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