MedGen

Angelman syndrome (AS) is characterized by severe developmental delay or intellectual disability, severe speech impairment, gait ataxia and/or tremulousness of the limbs, and unique behavior with an apparent happy demeanor that includes frequent laughing, smiling, and excitability. Microcephaly and seizures are also common. Developmental delays are first noted at around age six months; however, the unique clinical features of AS do not become manifest until after age one year. [from GeneReviews]

Prader-Willi syndrome (PWS) is characterized by severe hypotonia and feeding difficulties in early infancy, followed in later infancy or early childhood by excessive eating and gradual development of morbid obesity (unless eating is externally controlled). Motor milestones and language development are delayed. All individuals have some degree of cognitive impairment. A distinctive behavioral phenotype (with temper tantrums, stubbornness, manipulative behavior, and obsessive-compulsive characteristics) is common. Hypogonadism is present in both males and females and manifests as genital hypoplasia, incomplete pubertal development, and, in most, infertility. Short stature is common (if not treated with growth hormone); characteristic facial features, strabismus, and scoliosis are often present. [from GeneReviews]

Severe mental retardation is defined as an intelligence quotient (IQ) in the range of 20-34. [from HPO]

A type of chromosome rearrangement in which a segment has been turned through 180 degrees (inverted), and inserted back into its original location on the chromosome. [from NCI]

A seizure characterized by sensory phenomena including tingling, numbness, electric-shock like sensation, pain, sense of movement, or desire to move as its first clinical manifestation. [from HPO]

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. [from HPO]

Filippi syndrome is characterized by short stature, microcephaly, syndactyly, intellectual disability, and facial dysmorphism consisting of bulging forehead, broad and prominent nasal bridge, and diminished alar flare. Common features include cryptorchidism, speech impairment, and clinodactyly of the fifth finger, Some patients exhibit visual disturbances, polydactyly, seizures, and/or ectodermal abnormalities, such as nail hypoplasia, long eyelashes, hirsutism, and microdontia (summary by Hussain et al., 2014). [from OMIM]

This syndrome has characteristics of intellectual deficit, short stature, obesity, genital abnormalities, and hand and/or toe contractures. It has been described in two brothers and in one isolated case. This syndrome is similar to Prader-Willi syndrome, but the hand contractures and osteoporosis, together with the lack of hypotonia, indicate this is a different entity. [from SNOMEDCT_US]