Total 67 clinical symptoms reported for Kleefstra syndrome  Very Frequent (12)Occasional (33)Frequent (22)

Anteverted nares	Anteriorly-facing nostrils viewed with the head in the Frankfurt horizontal and the eyes of the observer level with the eyes of the subject. This gives the appearance of an upturned nose (upturned nasal tip).   Synonyms:Anteverted nose; Anteverted nostrils; Nasal tip, upturned; Nostrils anteverted; Upturned nares; Upturned nasal tip; Upturned nose; Upturned nostrils	Very frequent
Coarse facial features	Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues.   Synonyms:Coarse face; Coarse facial appearance; Coarse facial features; Coarse facies	Very frequent
Delayed speech and language development	A degree of language development that is significantly below the norm for a child of a specified age.   Synonyms:Deficiency of speech development; Delayed language development; Delayed speech; Delayed speech acquisition; Delayed speech and language development; Delayed speech development; Impaired speech and language development; Impaired speech development; Language delay; Language delayed; Language development deficit; Late-onset speech development; Poor language development; Speech and language delay; Speech and language difficulties; Speech delay	Very frequent
Everted lower lip vermilion	An abnormal configuration of the lower lip such that it is turned outward i.e., everted, with the Inner aspect of the lower lip vermilion (normally opposing the teeth) being visible in a frontal view.   Synonyms:Drooping lower lip; Eclabium of lower lip; Everted lower lip; Everted prominent lower lip; Outward turned lower lip	Very frequent
Exaggerated cupid's bow	More pronounced paramedian peaks and median notch of the Cupid's bow.   Synonyms:Cupid bow upper lip; Cupid's bow, accentuated; Cupid-bow shaped upper lip; Exaggerated cupid's bow; Prominent cupid-bow of upper lip	Very frequent
Global developmental delay	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.   Synonyms:Delayed cognitive development; Delayed development; Delayed developmental milestones; Delayed intellectual development; Delayed milestones; Delayed psychomotor development; Developmental delay; Developmental delay in early childhood; Developmental delay, global; Developmental retardation; Lack of psychomotor development; Motor and developmental delay; Psychomotor delay; Psychomotor development deficiency; Psychomotor development failure; Psychomotor developmental delay; Retarded development; Retarded mental development; Retarded psychomotor development	Very frequent
Hypertelorism	Interpupillary distance more than 2 SD above the mean (alternatively, the appearance of an increased interpupillary distance or widely spaced eyes).   Synonyms:Excessive orbital separation; Increased distance between eye sockets; Increased distance between eyes; Increased interpupillary distance; Ocular hypertelorism; Wide-set eyes; Widely spaced eyes; Widened interpupillary distance	Very frequent
Hypotonia	Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.   Synonyms:Low muscle tone; Low or weak muscle tone; Muscle hypotonia; Muscular hypotonia	Very frequent
Intellectual disability, severe	Severe mental retardation is defined as an intelligence quotient (IQ) in the range of 20-34.   Synonyms:Early and severe mental retardation; Intellectual disability, severe; Mental retardation, severe; Severe mental retardation	Very frequent
Malar flattening	Underdevelopment of the malar prominence of the jugal bone (zygomatic bone in mammals), appreciated in profile, frontal view, and/or by palpation.   Synonyms:Decreased size of malar bone; Depressed malar region; Flat cheekbone; Malar hypoplasia; Underdevelopment of malar bone; Zygomatic flattening	Very frequent
Short nose	Distance from nasion to subnasale more than two standard deviations below the mean, or alternatively, an apparently decreased length from the nasal root to the nasal tip.   Synonyms:Decreased length of nose; Hypoplastic nose; Nasal hypoplasia; Short nose; Shortened nose	Very frequent
Tented upper lip vermilion	Triangular appearance of the oral aperture with the apex in the midpoint of the upper vermilion and the lower vermilion forming the base.   Synonyms:Inverted V-shaped upper lip	Very frequent