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Polydactyly, postaxial, type A8(PAPA8)

MedGen UID:
Concept ID:
Congenital Abnormality
Gene (location): GLI1 (12q13.3)
Monarch Initiative: MONDO:0029130
OMIM®: 618123


Postaxial polydactyly type A8 (PAPA8) is characterized by the presence of postaxial extra digits (hexadactyly) on the hands and/or the feet. The anomalous digits are well formed and have nails (Palencia-Campos et al., 2017). For a discussion of genetic heterogeneity of postaxial polydactyly, see 174200. [from OMIM]

Clinical features

From HPO
Postaxial polydactyly
MedGen UID:
Concept ID:
Disease or Syndrome
Polydactyly refers to the occurrence of supernumerary digits and is the most frequent of congenital hand and foot deformities. Based on the location of the extra digits, polydactyly can be classified into preaxial, involving the thumb or great toe; postaxial, affecting the fifth digit; and central, involving the 3 central digits. Postaxial polydactyly (PAP) is further subclassified into 2 types: in type A, a well-formed extra digit articulates with the fifth or a sixth metacarpal, whereas in type B, a rudimentary, poorly developed extra digit is present (summary by Umm-e-Kalsoom et al., 2012). Genetic Heterogeneity of Postaxial Polydactyly Other forms of postaxial polydactyly type A include PAPA2 (602085) on chromosome 13q21; PAPA3 (607324) on chromosome 19p13; PAPA4 (608562) on chromosome 7q22; PAPA5 (263450) on chromosome 13q13; PAPA6 (615226), caused by mutation in the ZNF141 gene (194648) on chromosome 4p16; PAPA7 (617642), caused by mutation in the IQCE gene (617631) on chromosome 7p22; PAPA8 (618123), caused by mutation in the GLI1 gene (165220) on chromosome 12q13; PAPA9 (618219), caused by mutation in the FAM98A gene (617273) on chromosome 8q22; and PAPA10 (618498), caused by mutation in the KIAA0825 gene (617266) on chromosome 5q15.
Genu valgum
MedGen UID:
Concept ID:
Anatomical Abnormality
The legs angle inward, such that the knees are close together and the ankles far apart.
Short stature
MedGen UID:
Concept ID:
A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms).
Nail dysplasia
MedGen UID:
Concept ID:
Congenital Abnormality
The presence of developmental dysplasia of the nail.

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