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 CIBAR1 gene (617273) on chromosome 8q22; and PAPA10 (618498), caused by mutation in the KIAA0825 gene (617266) on chromosome 5q15.

A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter.

A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.

An abnormal curvature of the spine in both a coronal (lateral) and sagittal (back-to-front) plane.

The odontoid process, or dens, is a bony projection from the axis (C2) upward into the ring of the atlas (C1) at the top of the spine. During embryogenesis, the body of the odontoid derives from the centrum of the atlas and separates from the atlas, fusing with the superior portion of the axis. If the odontoid is hypoplastic or absent, the attachments for the apical and alar ligaments are missing, allowing for excessive rotation of the atlas, craniocervical instability, and possibly cord compression (summary by Stevens et al., 2009).

Increased volume and globular shape of the anteroinferior aspect of the nose.

The palpebral fissure inclination is more than two standard deviations below the mean.

Increased breadth of the nasal bridge (and with it, the nasal root).

Cleft palate is a developmental defect of the palate resulting from a failure of fusion of the palatine processes and manifesting as a separation of the roof of the mouth (soft and hard palate).