Short limb dwarfism Very fine thin light hairs and eyebrows Hyperextensible joints of hand and feet Abnormalities of spine Neutropenia Defective antibody and cell mediated immunity
CHH is an autosomal recessive[2] inherited disorder. It is a highly pleiotropic disorder. A rarely encountered genetic phenomenon, known as uniparental disomy (a genetic circumstance where a child inherits two copies of a chromosome from one parent, as opposed to one copy from each parent) has also been observed with the disorder.[2]
An association between mutations near or within the ncRNA component of RNase MRP, RMRP, has been identified.[3][4][5][6] The endoribonuclease RNase MRP is a complex of RNA molecule and several proteins and it participates in cleavage of mitochondrial primers responsible for DNA replication and in pre-rRNA processing in the nucleolus.[7][8] The locus of the gene has been mapped to the short arm of chromosome 9.[9]
Patients with CHH usually suffer from cellular immunodeficiency. In the study of 108 Finnish patients with CHH, there was detected mild to moderate form of lymphopenia, decreased delayed type of hypersensitivity and impaired responses to phytohemagglutinin.[10] This leads to susceptibility to and, in some more severe cases, mortality from infections early in childhood. There has also been detected combined immunodeficiency in some patients.[11]
Patients with CHH often have increased predispositions to malignancies.[11]
^James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology(10th ed.). Saunders. ISBN0-7216-2921-0.
^ abSulisalo T, Makitie O, Sistonen P, Ridanpaa M, el Rifai W, Ruuskanen O, de la Chapelle A, Kaitila L (1997). "Uniparental disomy in cartilage-hair hypoplasia". European Journal of Human Genetics. 5 (1): 35–42. doi:10.1159/000484729. PMID9156319.
^Bonafé L, Schmitt K, Eich G, Giedion A, Superti-Furga A (February 2002). "RMRP gene sequence analysis confirms a cartilage-hair hypoplasia variant with only skeletal manifestations and reveals a high density of single-nucleotide polymorphisms". Clinical Genetics. 61 (2): 146–51. doi:10.1034/j.1399-0004.2002.610210.x. PMID11940090. S2CID7284120.
^Hsieh, C. L.; Donlon, T. A.; Darras, B. T.; Chang, D. D.; Topper, J. N.; Clayton, D. A.; Francke, U (1990). "The gene for the RNA component of the mitochondrial RNA-processing endoribonuclease is located on human chromosome 9p and on mouse chromosome 4". Genomics. 6 (3): 540–544. doi:10.1016/0888-7543(90)90483-b. PMID2328993.
^Sulisalo, T; Sistonen, P; Hästbacka, J; Wadelius, C; Mäkitie, O; de la Chapelle, A; Kaitila, I (1993). "Cartilage-hair hypoplasia gene assigned to chromosome 9 by linkage analysis". Nature Genetics. 3 (4): 338–341. doi:10.1038/ng0493-338. PMID7981754. S2CID7752268.
^Mäkitie, O; Kaitila, I (1993). "Cartilage-hair hypoplasia--clinical manifestations in 108 Finnish patients". European Journal of Pediatrics. 152 (3): 211–7. doi:10.1007/bf01956147. PMID8444246. S2CID10611620.
^ abSaulsbury, F. T.; Winkelstein, J. A.; Davis, L. E.; Hsu, S. H.; d'Souza, B. J.; Gutcher, G. R.; Butler, I. J. (1975). "Combined immunodeficiency and vaccine-related poliomyelitis in a child with cartilage-hair hypoplasia". The Journal of Pediatrics. 86 (6): 868–72. doi:10.1016/s0022-3476(75)80216-2. PMID165279.
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