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Short-rib thoracic dysplasia 21 without polydactyly(SRTD21)

MedGen UID:
1794171
Concept ID:
C5561961
Disease or Syndrome
Synonyms: SHORT-RIB THORACIC DYSPLASIA 21 WITHOUT POLYDACTYLY; SRTD21
 
Gene (location): KIAA0753 (17p13.1)
 
Monarch Initiative: MONDO:0030356
OMIM®: 619479

Definition

Short-rib thoracic dysplasia-21 (SRTD21) is characterized by rhizomelic limb shortening with bowing of long bones and metaphyseal abnormalities, narrow chest with short broad ribs, and trident pelvis. Other features include hypotonia and global developmental delay, with corpus callosum hypoplasia and cerebellar vermis abnormalities on brain imaging, which may show the 'molar tooth' sign (Hammarsjo et al., 2017). For a general phenotypic description and discussion of genetic heterogeneity of SRTD, see SRTD1 (208500). Mutation in the KIAA0753 gene also causes orofaciodigital syndrome (OFD15; 617127) and Joubert syndrome (JBTS28; 619476), phenotypes with features overlapping those of SRTD21. [from OMIM]

Clinical features

From HPO
Hypospadias
MedGen UID:
163083
Concept ID:
C0848558
Congenital Abnormality
Abnormal position of urethral meatus on the ventral penile shaft (underside) characterized by displacement of the urethral meatus from the tip of the glans penis to the ventral surface of the penis, scrotum, or perineum.
Micropenis
MedGen UID:
1633603
Concept ID:
C4551492
Congenital Abnormality
Abnormally small penis. At birth, the normal penis is about 3 cm (stretched length from pubic tubercle to tip of penis) with micropenis less than 2.0-2.5 cm.
Brachydactyly
MedGen UID:
67454
Concept ID:
C0221357
Congenital Abnormality
Digits that appear disproportionately short compared to the hand/foot. The word brachydactyly is used here to describe a series distinct patterns of shortened digits (brachydactyly types A-E). This is the sense used here.
Short humerus
MedGen UID:
316907
Concept ID:
C1832117
Congenital Abnormality
Underdevelopment of the humerus.
Bowed humerus
MedGen UID:
395269
Concept ID:
C1859460
Finding
A bending or abnormal curvature of the humerus.
Trident pelvis
MedGen UID:
1795576
Concept ID:
C5563366
Congenital Abnormality
Spurs at the medial and lateral acetabular margin and in the center of the acetabulum gives rise to shape resembling a three-pronged spear known as trident.
Disproportionate short-limb short stature
MedGen UID:
342370
Concept ID:
C1849937
Finding
A type of disproportionate short stature characterized by a short limbs but an average-sized trunk.
Tube feeding
MedGen UID:
8641
Concept ID:
C0014327
Therapeutic or Preventive Procedure
Feeding problem necessitating food and nutrient delivery via a tube.
Feeding difficulties
MedGen UID:
65429
Concept ID:
C0232466
Finding
Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.
Protuberant abdomen
MedGen UID:
340750
Concept ID:
C1854928
Finding
A thrusting or bulging out of the abdomen.
Low-set ears
MedGen UID:
65980
Concept ID:
C0239234
Congenital Abnormality
Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the 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).
Hypoplasia of the corpus callosum
MedGen UID:
138005
Concept ID:
C0344482
Congenital Abnormality
Underdevelopment of the corpus callosum.
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.
Delayed gross motor development
MedGen UID:
332508
Concept ID:
C1837658
Finding
A type of motor delay characterized by a delay in acquiring the ability to control the large muscles of the body for walking, running, sitting, and crawling.
Lateral ventricle dilatation
MedGen UID:
383904
Concept ID:
C1856409
Pathologic Function
Molar tooth sign on MRI
MedGen UID:
400670
Concept ID:
C1865060
Finding
An abnormal appearance of the midbrain in axial magnetic resonance imaging in which the elongated superior cerebellar peduncles give the midbrain an appearance reminiscent of a molar or wisdom tooth.
Ventriculomegaly
MedGen UID:
480553
Concept ID:
C3278923
Finding
An increase in size of the ventricular system of the brain.
Small pituitary gland
MedGen UID:
868479
Concept ID:
C4022873
Anatomical Abnormality
An abnormally decreased size of the pituitary gland.
Dysgenesis of the cerebellar vermis
MedGen UID:
871238
Concept ID:
C4025719
Anatomical Abnormality
Defective development of the vermis of cerebellum.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
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.
Frontal bossing
MedGen UID:
67453
Concept ID:
C0221354
Congenital Abnormality
Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline.
Flexion contracture
MedGen UID:
83069
Concept ID:
C0333068
Anatomical Abnormality
A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints.
Narrow chest
MedGen UID:
96528
Concept ID:
C0426790
Finding
Reduced width of the chest from side to side, associated with a reduced distance from the sternal notch to the tip of the shoulder.
Thoracic hypoplasia
MedGen UID:
373339
Concept ID:
C1837482
Congenital Abnormality
Short long bone
MedGen UID:
344385
Concept ID:
C1854912
Finding
One or more abnormally short long bone.
Neonatal respiratory distress
MedGen UID:
924182
Concept ID:
C4281993
Finding
Respiratory difficulty as newborn.
Microdontia
MedGen UID:
66008
Concept ID:
C0240340
Congenital Abnormality
Decreased size of the teeth, which can be defined as a mesiodistal tooth diameter (width) more than 2 SD below mean. Alternatively, an apparently decreased maximum width of tooth.
Short lingual frenulum
MedGen UID:
604928
Concept ID:
C0426501
Finding
The presence of an abnormally short lingual frenulum.
Depressed nasal bridge
MedGen UID:
373112
Concept ID:
C1836542
Finding
Posterior positioning of the nasal root in relation to the overall facial profile for age.
Widely spaced teeth
MedGen UID:
337093
Concept ID:
C1844813
Finding
Increased spaces (diastemata) between most of the teeth in the same dental arch.
Wide nasal bridge
MedGen UID:
341441
Concept ID:
C1849367
Finding
Increased breadth of the nasal bridge (and with it, the nasal root).
Flat face
MedGen UID:
342829
Concept ID:
C1853241
Finding
Absence of concavity or convexity of the face when viewed in profile.
Long philtrum
MedGen UID:
351278
Concept ID:
C1865014
Finding
Distance between nasal base and midline upper lip vermilion border more than 2 SD above the mean. Alternatively, an apparently increased distance between nasal base and midline upper lip vermilion border.
Hypertrichosis
MedGen UID:
43787
Concept ID:
C0020555
Disease or Syndrome
Hypertrichosis is increased hair growth that is abnormal in quantity or location.

Recent clinical studies

Etiology

Fontana P, Agolini E, Cocciadiferro D, Mazzarelli LL, Di Meglio A, Novelli A, Scarano G, Lombardi C, Ciavarella M, Lonardo F
J Matern Fetal Neonatal Med 2023 Dec;36(1):2205985. doi: 10.1080/14767058.2023.2205985. PMID: 37100787
Daskalakis G, Souka AP, Kavalakis I, Haritos T, Basayiannis C, Antsaklis P, Antsaklis A
Fetal Diagn Ther 2006;21(5):401-3. doi: 10.1159/000093879. PMID: 16912486

Diagnosis

Fontana P, Agolini E, Cocciadiferro D, Mazzarelli LL, Di Meglio A, Novelli A, Scarano G, Lombardi C, Ciavarella M, Lonardo F
J Matern Fetal Neonatal Med 2023 Dec;36(1):2205985. doi: 10.1080/14767058.2023.2205985. PMID: 37100787
Daskalakis G, Souka AP, Kavalakis I, Haritos T, Basayiannis C, Antsaklis P, Antsaklis A
Fetal Diagn Ther 2006;21(5):401-3. doi: 10.1159/000093879. PMID: 16912486
Meizner I, Barnhard Y
Prenat Diagn 1995 Jul;15(7):665-8. doi: 10.1002/pd.1970150713. PMID: 8532628

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