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Syndromic X-linked intellectual disability Siderius type(MRXSSD)

MedGen UID:
337375
Concept ID:
C1846055
Disease or Syndrome
Synonyms: Intellectual deficit X-linked Siderius type; INTELLECTUAL DEVELOPMENTAL DISORDER, X-LINKED, SYNDROMIC, SIDERIUS TYPE; MRXSSD; Siderius Hamel syndrome
Modes of inheritance:
X-linked recessive inheritance
MedGen UID:
375779
Concept ID:
C1845977
Finding
Source: Orphanet
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.
 
Gene (location): PHF8 (Xp11.22)
 
Monarch Initiative: MONDO:0010286
OMIM®: 300263
Orphanet: ORPHA85287

Definition

Siderius-type syndromic intellectual developmental disorder (MRXSSD) is an X-linked disorder in which affected males have mildly impaired intellectual development, mild dysmorphic features, and bilateral or unilateral cleft lip/palate (summary by Koivisto et al., 2007). [from OMIM]

Additional description

From MedlinePlus Genetics
X-linked intellectual disability, Siderius type is a condition characterized by mild to moderate intellectual disability that affects only males. Affected boys often have delayed development of motor skills such as walking, and their speech may be delayed.

Individuals with X-linked intellectual disability, Siderius type frequently also have an opening in the lip (cleft lip) with an opening in the roof of the mouth (cleft palate). A cleft can occur on one or both sides of the upper lip.

Some boys and men with this condition have distinctive facial features, including a long face, a sloping forehead, a broad nasal bridge, a prominent bone in the lower forehead (supraorbital ridge), and outside corners of the eyes that point upward (upslanting palpebral fissures). Affected individuals may also have low-set ears and large hands.  https://medlineplus.gov/genetics/condition/x-linked-intellectual-disability-siderius-type

Clinical features

From HPO
Arachnodactyly
MedGen UID:
2047
Concept ID:
C0003706
Congenital Abnormality
Abnormally long and slender fingers (spider fingers).
Pes planus
MedGen UID:
42034
Concept ID:
C0016202
Anatomical Abnormality
A foot where the longitudinal arch of the foot is in contact with the ground or floor when the individual is standing; or, in a patient lying supine, a foot where the arch is in contact with the surface of a flat board pressed against the sole of the foot by the examiner with a pressure similar to that expected from weight bearing; or, the height of the arch is reduced.
Large hands
MedGen UID:
98097
Concept ID:
C0426870
Finding
Long toe
MedGen UID:
461963
Concept ID:
C3150613
Finding
Toes that appear disproportionately long compared to the foot.
Intellectual disability, mild
MedGen UID:
10044
Concept ID:
C0026106
Mental or Behavioral Dysfunction
Mild intellectual disability is defined as an intelligence quotient (IQ) in the range of 50-69.
Delayed speech and language development
MedGen UID:
105318
Concept ID:
C0454644
Finding
A degree of language development that is significantly below the norm for a child of a specified age.
Intellectual disability
MedGen UID:
811461
Concept ID:
C3714756
Mental or Behavioral Dysfunction
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.
Thoracic kyphosis
MedGen UID:
263148
Concept ID:
C1184919
Finding
Over curvature of the thoracic region, leading to a round back or if sever to a hump.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Hypernasal speech
MedGen UID:
99115
Concept ID:
C0454555
Finding
A type of speech characterized by the presence of an abnormally increased nasal airflow during speech associated with structural abnormality of the nasal passages.
Upslanted palpebral fissure
MedGen UID:
98390
Concept ID:
C0423109
Finding
The palpebral fissure inclination is more than two standard deviations above the mean for age (objective); or, the inclination of the palpebral fissure is greater than typical for age.
Broad nasal tip
MedGen UID:
98424
Concept ID:
C0426429
Finding
Increase in width of the nasal tip.
Long face
MedGen UID:
324419
Concept ID:
C1836047
Finding
Facial height (length) is more than 2 standard deviations above the mean (objective); or, an apparent increase in the height (length) of the face (subjective).
Prominent supraorbital ridges
MedGen UID:
333982
Concept ID:
C1842060
Finding
Greater than average forward and/or lateral protrusion of the supraorbital portion of the frontal bones.
Low posterior hairline
MedGen UID:
383755
Concept ID:
C1855728
Finding
Hair on the neck extends more inferiorly than usual.
Sloping forehead
MedGen UID:
346640
Concept ID:
C1857679
Finding
Inclination of the anterior surface of the forehead from the vertical more than two standard deviations above the mean (objective); or apparently excessive posterior sloping of the forehead in a lateral view.
Cleft palate
MedGen UID:
756015
Concept ID:
C2981150
Congenital Abnormality
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).
Cleft lip
MedGen UID:
1370297
Concept ID:
C4321245
Anatomical Abnormality
A gap in the lip or lips.
Synophrys
MedGen UID:
98132
Concept ID:
C0431447
Congenital Abnormality
Meeting of the medial eyebrows in the midline.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVSyndromic X-linked intellectual disability Siderius type
Follow this link to review classifications for Syndromic X-linked intellectual disability Siderius type in Orphanet.

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