- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Seizure (HP:0001250): 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. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Gait ataxia (HP:0002066): A type of ataxia characterized by the impairment of the ability to coordinate the movements required for normal walking. Gait ataxia is characteirzed by a wide-based staggering gait with a tendency to fall. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Narrow mouth (HP:0000160): Distance between the commissures of the mouth more than 2 SD below the mean. Alternatively, an apparently decreased width of the oral aperture (subjective). Evidence: PCS. (PMID:17088400)
- Gastroesophageal reflux (HP:0002020): A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter. Evidence: PCS. (PMID:17088400)
- 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. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup;PMID:17088400)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Depression (HP:0000716): Frequently experiencing feelings of being down, miserable, and/or hopeless; struggling to recover from these moods; having a pessimistic outlook on the future; feeling a pervasive sense of shame; having a low self-worth; experiencing thoughts of suicide and engaging in suicidal behavior. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Autism (HP:0000717): Autism is a neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. Autism begins in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual (DSM-IV). Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Anxiety (HP:0000739): Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Feeding difficulties in infancy (HP:0008872): Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Motor stereotypy (HP:0000733): Use of the same abnormal action in response to certain triggers or at random. They may be used as a way to regulate one's internal state but must otherwise have no apparent functional purpose. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Constipation (HP:0002019): Infrequent or difficult evacuation of feces. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. (PMID:17088400)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: PCS. (PMID:17088400)
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- 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: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Malar flattening (HP:0000272): Underdevelopment of the malar prominence of the jugal bone (zygomatic bone in mammals), appreciated in profile, frontal view, and/or by palpation. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Progressive spasticity (HP:0002191): Spasticity that increases in degree with time. Evidence: PCS. Onset: Juvenile onset (HP:0003621). (PMID:17088400)
- Depressed nasal bridge (HP:0005280): Posterior positioning of the nasal root in relation to the overall facial profile for age. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Death in childhood (HP:0003819): Death in during childhood, defined here as between the ages of 2 and 10 years. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- X-linked recessive inheritance (HP:0001419): A mode of inheritance that is observed for recessive traits related to a gene encoded on the X chromosome. In the context of medical genetics, X-linked recessive disorders manifest in males (who have one copy of the X chromosome and are thus hemizygotes), but generally not in female heterozygotes who have one mutant and one normal allele. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Neonatal hypotonia (HP:0001319): Muscular hypotonia (abnormally low muscle tone) manifesting in the neonatal period. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Functional abnormality of the bladder (HP:0000009): Dysfunction of the urinary bladder. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Drooling (HP:0002307): Habitual flow of saliva out of the mouth. Evidence: PCS. (PMID:17088400)
- Recurrent respiratory infections (HP:0002205): An increased susceptibility to respiratory infections as manifested by a history of recurrent respiratory infections. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Macrotia (HP:0000400): Median longitudinal ear length greater than two standard deviations above the mean and median ear width greater than two standard deviations above the mean (objective); or, apparent increase in length and width of the pinna (subjective). Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Brachycephaly (HP:0000248): An abnormality of skull shape characterized by a decreased anterior-posterior diameter. That is, a cephalic index greater than 81%. Alternatively, an apparently shortened anteroposterior dimension (length) of the head compared to width. Evidence: IEA. (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=mecp2-dup)
- Decreased circulating IgA concentration (HP:0002720): Decreased levels of immunoglobulin A (IgA). Evidence: PCS. Onset: Juvenile onset (HP:0003621). (PMID:17088400)
These phenotypes are associated with the disease syndromic X-linked intellectual disability Lubs type (DECIPHER:45).