U.S. flag

An official website of the United States government

Format

Send to:

Choose Destination

Thrombocytopenia 8, with dysmorphic features and developmental delay(THC8)

MedGen UID:
1851006
Concept ID:
C5882677
Disease or Syndrome
Synonyms: THC8; THROMBOCYTOPENIA, AUTOSOMAL DOMINANT, 8
 
Gene (location): ACTB (7p22.1)
 
OMIM®: 620475

Definition

Thrombocytopenia-8 with dysmorphic features and developmental delay (THC8) is an autosomal dominant syndromic disorder characterized by early-childhood onset of chronic thrombocytopenia with anisotropy and immature enlarged platelets, usually without spontaneous bleeding episodes. Affected individuals have dysmorphic facial features and variable developmental delay with speech delay and mildly impaired intellectual development (Latham et al., 2018). For a discussion of genetic heterogeneity of thrombocytopenia, see 313900. [from OMIM]

Clinical features

From HPO
Overlapping toe
MedGen UID:
182531
Concept ID:
C0920299
Anatomical Abnormality
Describes a foot digit resting on the dorsal surface of an adjacent digit when the foot is at rest. Initially clawing may be dynamic and only noticeable on walking. Over time the plantar plate tears, subluxation occurs at the metatarsophalangeal joint (MTPJ), and the deformity becomes permanent.
Patent ductus arteriosus
MedGen UID:
4415
Concept ID:
C0013274
Congenital Abnormality
In utero, the ductus arteriosus (DA) serves to divert ventricular output away from the lungs and toward the placenta by connecting the main pulmonary artery to the descending aorta. A patent ductus arteriosus (PDA) in the first 3 days of life is a physiologic shunt in healthy term and preterm newborn infants, and normally is substantially closed within about 24 hours after bith and completely closed after about three weeks. Failure of physiologcal closure is referred to a persistent or patent ductus arteriosus (PDA). Depending on the degree of left-to-right shunting, PDA can have clinical consequences.
Ventricular arrhythmia
MedGen UID:
39082
Concept ID:
C0085612
Disease or Syndrome
A disorder characterized by an electrocardiographic finding of an atypical cardiac rhythm resulting from a pathologic process in the cardiac ventricles.
Microtia
MedGen UID:
57535
Concept ID:
C0152423
Congenital Abnormality
Underdevelopment of the external ear.
Posteriorly rotated ears
MedGen UID:
96566
Concept ID:
C0431478
Congenital Abnormality
A type of abnormal location of the ears in which the position of the ears is characterized by posterior rotation (the superior part of the ears is rotated towards the back of the head, and the inferior part of the ears towards the front).
Hearing impairment
MedGen UID:
235586
Concept ID:
C1384666
Disease or Syndrome
A decreased magnitude of the sensory perception of sound.
Overfolded helix
MedGen UID:
325239
Concept ID:
C1837731
Finding
A condition in which the helix is folded over to a greater degree than normal. That is, excessive curling of the helix edge, whereby the free edge is parallel to the plane of the ear.
Seizure
MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
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.
Gray matter heterotopia
MedGen UID:
452349
Concept ID:
C0266491
Finding
Heterotopia or neuronal heterotopia are macroscopic clusters of misplaced neurons (gray matter), most often situated along the ventricular walls or within the subcortical white matter.
Lower limb spasticity
MedGen UID:
220865
Concept ID:
C1271100
Finding
Spasticity (velocity-dependent increase in tonic stretch reflexes with increased muscle tone and hyperexcitable tendon reflexes) in the muscles of the lower limbs, hips, and pelvis.
Mild global developmental delay
MedGen UID:
861405
Concept ID:
C4012968
Finding
A mild delay in the achievement of motor or mental milestones in the domains of development of a child.
Thrombocytopenia
MedGen UID:
52737
Concept ID:
C0040034
Disease or Syndrome
A reduction in the number of circulating thrombocytes.
Increased mean platelet volume
MedGen UID:
853131
Concept ID:
C1096367
Finding
Average platelet volume above the upper limit of the normal reference interval.
Platelet anisocytosis
MedGen UID:
810926
Concept ID:
C1739105
Pathologic Function
Abnormally increased variability in the size of platelets.
Umbilical hernia
MedGen UID:
9232
Concept ID:
C0019322
Anatomical Abnormality
Protrusion of abdominal contents through a defect in the abdominal wall musculature around the umbilicus. Skin and subcutaneous tissue overlie the defect.
Prominent metopic ridge
MedGen UID:
387953
Concept ID:
C1857949
Finding
Vertical bony ridge positioned in the midline of the forehead.
Anti-platelet antigen antibody positivity
MedGen UID:
1841771
Concept ID:
C5826899
Laboratory or Test Result
The presence of autoantibodies (immunoglobulins) in the serum that react against antigens present on the surface of thrombocytes such as the glycoproteins GPIIb/IIIa, GPIb/IX, and GPIa/IIa.
Wide mouth
MedGen UID:
44238
Concept ID:
C0024433
Congenital Abnormality
Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective).
Bulbous nose
MedGen UID:
66013
Concept ID:
C0240543
Finding
Increased volume and globular shape of the anteroinferior aspect of the nose.
High palate
MedGen UID:
66814
Concept ID:
C0240635
Congenital Abnormality
Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective).
Mandibular prognathia
MedGen UID:
98316
Concept ID:
C0399526
Finding
Abnormal prominence of the chin related to increased length of the mandible.
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.
Telecanthus
MedGen UID:
140836
Concept ID:
C0423113
Finding
Distance between the inner canthi more than two standard deviations above the mean (objective); or, apparently increased distance between the inner canthi.
Broad nasal tip
MedGen UID:
98424
Concept ID:
C0426429
Finding
Increase in width of the nasal tip.
Epicanthus
MedGen UID:
151862
Concept ID:
C0678230
Congenital Abnormality
Epicanthus is a condition in which a fold of skin stretches from the upper to the lower eyelid, partially covering the inner canthus. Usher (1935) noted that epicanthus is a normal finding in the fetus of all races. Epicanthus also occurs in association with hereditary ptosis (110100).
Pointed chin
MedGen UID:
336193
Concept ID:
C1844505
Finding
A marked tapering of the lower face to the chin.
Wide nasal bridge
MedGen UID:
341441
Concept ID:
C1849367
Finding
Increased breadth of the nasal bridge (and with it, the nasal root).
Midface retrusion
MedGen UID:
339938
Concept ID:
C1853242
Anatomical Abnormality
Posterior positions and/or vertical shortening of the infraorbital and perialar regions, or increased concavity of the face and/or reduced nasolabial angle.
Broad eyebrow
MedGen UID:
344657
Concept ID:
C1856121
Finding
Regional increase in the width (height) of the eyebrow.
Thin upper lip vermilion
MedGen UID:
355352
Concept ID:
C1865017
Finding
Height of the vermilion of the upper lip in the midline more than 2 SD below the mean. Alternatively, an apparently reduced height of the vermilion of the upper lip in the frontal view (subjective).
Horizontal eyebrow
MedGen UID:
478649
Concept ID:
C3277019
Finding
An eyebrow that extends straight across the brow, without curve.
Synophrys
MedGen UID:
98132
Concept ID:
C0431447
Congenital Abnormality
Meeting of the medial eyebrows in the midline.
Long eyelashes
MedGen UID:
342955
Concept ID:
C1853738
Finding
Mid upper eyelash length >10 mm or increased length of the eyelashes (subjective).
Polyhydramnios
MedGen UID:
6936
Concept ID:
C0020224
Pathologic Function
The presence of excess amniotic fluid in the uterus during pregnancy.
Deeply set eye
MedGen UID:
473112
Concept ID:
C0423224
Finding
An eye that is more deeply recessed into the plane of the face than is typical.

Recent clinical studies

Etiology

Peixoto de Barcelos I, Jan AK, Modesti N, Woidill S, Gavazzi F, Isaacs D, D'Aiello R, Sevagamoorthy A, Charlton L, Pizzino A, Schmidt J, van Haren K, Keller S, Eichler F, Emrick LT, Fraser JL, Shults J, Vanderver A, Adang LA
Mol Genet Metab 2024 Sep-Oct;143(1-2):108578. Epub 2024 Sep 15 doi: 10.1016/j.ymgme.2024.108578. PMID: 39332260
Munro SC, Trincado D, Hall B, Rawlinson WD
J Paediatr Child Health 2005 Aug;41(8):449-52. doi: 10.1111/j.1440-1754.2005.00665.x. PMID: 16101982

Diagnosis

Peixoto de Barcelos I, Jan AK, Modesti N, Woidill S, Gavazzi F, Isaacs D, D'Aiello R, Sevagamoorthy A, Charlton L, Pizzino A, Schmidt J, van Haren K, Keller S, Eichler F, Emrick LT, Fraser JL, Shults J, Vanderver A, Adang LA
Mol Genet Metab 2024 Sep-Oct;143(1-2):108578. Epub 2024 Sep 15 doi: 10.1016/j.ymgme.2024.108578. PMID: 39332260
Masuoka S, Tanaka T, Kanaji M, Furukawa K, Koshiba K, Yamada Z, Watanabe E, Kawazoe M, Ito S, Fuchigami A, Nanki T
Mod Rheumatol Case Rep 2024 Jul 8;8(2):280-285. doi: 10.1093/mrcr/rxae004. PMID: 38252597
Kose CC, Kaya D, Akcan MB, Silan F
Am J Med Genet A 2023 Aug;191(8):2209-2214. Epub 2023 May 15 doi: 10.1002/ajmg.a.63244. PMID: 37190896
Munro SC, Trincado D, Hall B, Rawlinson WD
J Paediatr Child Health 2005 Aug;41(8):449-52. doi: 10.1111/j.1440-1754.2005.00665.x. PMID: 16101982

Therapy

Peixoto de Barcelos I, Jan AK, Modesti N, Woidill S, Gavazzi F, Isaacs D, D'Aiello R, Sevagamoorthy A, Charlton L, Pizzino A, Schmidt J, van Haren K, Keller S, Eichler F, Emrick LT, Fraser JL, Shults J, Vanderver A, Adang LA
Mol Genet Metab 2024 Sep-Oct;143(1-2):108578. Epub 2024 Sep 15 doi: 10.1016/j.ymgme.2024.108578. PMID: 39332260

Prognosis

Peixoto de Barcelos I, Jan AK, Modesti N, Woidill S, Gavazzi F, Isaacs D, D'Aiello R, Sevagamoorthy A, Charlton L, Pizzino A, Schmidt J, van Haren K, Keller S, Eichler F, Emrick LT, Fraser JL, Shults J, Vanderver A, Adang LA
Mol Genet Metab 2024 Sep-Oct;143(1-2):108578. Epub 2024 Sep 15 doi: 10.1016/j.ymgme.2024.108578. PMID: 39332260

Clinical prediction guides

Peixoto de Barcelos I, Jan AK, Modesti N, Woidill S, Gavazzi F, Isaacs D, D'Aiello R, Sevagamoorthy A, Charlton L, Pizzino A, Schmidt J, van Haren K, Keller S, Eichler F, Emrick LT, Fraser JL, Shults J, Vanderver A, Adang LA
Mol Genet Metab 2024 Sep-Oct;143(1-2):108578. Epub 2024 Sep 15 doi: 10.1016/j.ymgme.2024.108578. PMID: 39332260

Supplemental Content

Recent activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...