Phenotypes associated with the disease megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 3 (OMIM:615938):
- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. (PMID:24705253)
- Megalencephaly (HP:0001355): Diffuse enlargement of the entire cerebral hemispheres leading to macrocephaly (with or without overlying cortical dysplasia). Evidence: PCS. Frequency: 12/12. (PMID:24705253)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: IEA. (OMIM:615938)
- Postaxial hand polydactyly (HP:0001162): Supernumerary digits located at the ulnar side of the hand (that is, on the side with the fifth finger). Evidence: PCS. Frequency: 11/12. (PMID:24705253)
- Global developmental delay (HP:0001263): A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age. Evidence: PCS. Frequency: 11/11. (PMID:24705253)
- Severe intellectual disability (HP:0010864): Severe intellectual disability (ID) is defined as a type of ID characterized by severely sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 20-34. Evidence: PCS. Frequency: 10/11. (PMID:24705253)
- Thick corpus callosum (HP:0007074): Increased vertical dimension of the corpus callosum. This feature can be visualized by sagittal sections on magnetic resonance tomography imaging of the brain. Evidence: PCS. Frequency: 1/12. (PMID:24705253)
- Prominent forehead (HP:0011220): Forward prominence of the entire forehead, due to protrusion of the frontal bone. Evidence: PCS. (PMID:24705253)
- Hydrocephalus (HP:0000238): Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation. Evidence: PCS. (PMID:24705253)
- Ventriculomegaly (HP:0002119): An increase in size of the ventricular system of the brain. Evidence: PCS. Frequency: 10/12. (PMID:24705253)
- Syndactyly (HP:0001159): Webbing or fusion of the fingers or toes, involving soft parts only or including bone structure. Bony fusions are referred to as "bony" syndactyly if the fusion occurs in a radio-ulnar axis. Fusions of bones of the fingers or toes in a proximo-distal axis are referred to as "symphalangism". Evidence: PCS. Frequency: 0/12. (PMID:24705253)
- Macrocephaly (HP:0000256): Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium. Evidence: PCS. (PMID:24705253)
- Polymicrogyria (HP:0002126): Polymicrogyria is a congenital malformation of the cerebral cortex characterized by abnormal cortical layering (lamination) and an excessive number of small gyri (folds). Evidence: PCS. Frequency: 12/12. (PMID:24705253)
- Autosomal dominant inheritance (HP:0000006): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:24705253)