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RH-NULL, AMORPH TYPE(RHNA)

MedGen UID:
1639338
Concept ID:
C4693796
Disease or Syndrome
Synonym: RHNA
 
RHCE (1p36.11)
 
OMIM®: 617970

Definition

The RH-null phenotype designates rare individuals whose red blood cells lack all Rh antigens. Two RH-null types, the regulator type (RHNR; 268150) and the amorph type (RHNA), arising from independent genetic mechanisms have been distinguished. The regulator type is caused by mutation in the RHAG gene (180297). The amorph type arises from mutations at the RH locus itself that silence Rh expression. The RH locus contains the RHD (111680) and RHCE genes tandemly arranged at chromosome 1p36-p34. Four genes must therefore be silenced to produce the RH-null phenotype. The absence of the D antigen, produced by the RHD gene, is common in the human population; the D-negative phenotype may result from deletion or genetic alteration of the RHD gene. The RH-null amorph phenotype thus arises from inactivating mutations in RHCE on a D-negative background (summary by Huang et al., 1998 and Huang et al., 2000). Clinically, Rh-null patients present mild to moderate hemolytic anemia; cells exhibit characteristic morphologic and functional abnormalities including spherocytosis, stomatocytosis, and diminished lifespan. Rh-null patients rarely develop antibodies without stimulation, and most cases occur in response to pregnancy or transfusion (Silvy et al., 2015). [from OMIM]

Clinical features

From HPO

Recent clinical studies

Etiology

Kulkarni SS, Vasantha K, Gogri H, Parchure D, Madkaikar M, Férec C, Fichou Y
Transfusion 2017 Aug;57(8):1944-1948. Epub 2017 May 3 doi: 10.1111/trf.14150. PMID: 28470789
Silvy M, Beley S, Peyrard T, Ouchari M, Abdelkefi S, Jemni Yacoub S, Chiaroni J, Bailly P
Transfusion 2015 Jun;55(6 Pt 2):1407-10. Epub 2014 Nov 21 doi: 10.1111/trf.12937. PMID: 25413218
Rosa KA, Reid ME, Lomas-Francis C, Powell VI, Costa FF, Stinghen ST, Watanabe AM, Carboni EK, Baldon JP, Jucksch MM, Castilho L
Transfusion 2005 Nov;45(11):1796-8. doi: 10.1111/j.1537-2995.2005.00605.x. PMID: 16271106
Carritt B, Blunt T, Avent N, Daniels G, Steers F
Ann Hum Genet 1993 Oct;57(4):273-9. doi: 10.1111/j.1469-1809.1993.tb00900.x. PMID: 7910003

Therapy

Silvy M, Beley S, Peyrard T, Ouchari M, Abdelkefi S, Jemni Yacoub S, Chiaroni J, Bailly P
Transfusion 2015 Jun;55(6 Pt 2):1407-10. Epub 2014 Nov 21 doi: 10.1111/trf.12937. PMID: 25413218

Prognosis

Silvy M, Beley S, Peyrard T, Ouchari M, Abdelkefi S, Jemni Yacoub S, Chiaroni J, Bailly P
Transfusion 2015 Jun;55(6 Pt 2):1407-10. Epub 2014 Nov 21 doi: 10.1111/trf.12937. PMID: 25413218
Rosa KA, Reid ME, Lomas-Francis C, Powell VI, Costa FF, Stinghen ST, Watanabe AM, Carboni EK, Baldon JP, Jucksch MM, Castilho L
Transfusion 2005 Nov;45(11):1796-8. doi: 10.1111/j.1537-2995.2005.00605.x. PMID: 16271106

Clinical prediction guides

Silvy M, Beley S, Peyrard T, Ouchari M, Abdelkefi S, Jemni Yacoub S, Chiaroni J, Bailly P
Transfusion 2015 Jun;55(6 Pt 2):1407-10. Epub 2014 Nov 21 doi: 10.1111/trf.12937. PMID: 25413218
Rosa KA, Reid ME, Lomas-Francis C, Powell VI, Costa FF, Stinghen ST, Watanabe AM, Carboni EK, Baldon JP, Jucksch MM, Castilho L
Transfusion 2005 Nov;45(11):1796-8. doi: 10.1111/j.1537-2995.2005.00605.x. PMID: 16271106

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