Dysmorphology Flashcards
What is dysmorphology?
The study of human congenital malformations (birth defects), particularly those affecting the anatomy (morphology) of the individual.
May be:
- Facial
- Skeletal
- Anatomical
What are some causes/reasons for dysmorphisms?
- Malformation: structural defect due to abnormal embryonic or fetal development
- Deformation: abnormality caused by physical stress to normal tissue
- Disruption: alteration of normally forming structures by extrinsic process
- Dysplasia: abnormal development/organization of cells or tissues
What are some ground rules for dysmorphic features?
- Everyone has at least 1 dysmorphic feature.
- Most genetic syndromes have several dysmorphic features involving more than one system.
- It’s the constellation of findings that makes the diagnosis
Where to start with the evaluation of dysmorphic features?
- Height
- Weight
- FOC
- Shape
- Proprotions
Head size is a key feature of what disorder?
Achondroplasia
What is the definition of macrocephaly?
FOC > 98th percentile
What is Rhizomelic short stature?
Disproportionate short stature
- Short proximal segments of limbs
(The opposite is mesomelic; disproportionate short stature with short distal segments of limbs)
What is the definition of microcephaly?
FOC < 2nd percentile
What syndromes is microcephaly seen in?
- Rubinstein Taybi syndrome (left)
- Seckel syndrome (right)
- Others
Microbrachycephaly is seen in what condition?
Down syndrome
Label the sutures
Think about the deformities that would occur if a suture closes too early
What is brachycephaly?
Short AP length of skull
What is dolichocephaly?
Long AP length of skull
What is trigonocephaly?
Triangular-shaped skull
What is turricephaly?
Tall head
What is craniosynostosis? What condition is it seen in?
Apert syndrome
What are the criteria for determining if the ears are low set?
- Draw a line from medial canthi and extend across to the ears
- This line should cross the superior attachment of the ear
What is one condition with low set ears?
- Other clinical associations
Noonan syndrome
- Also associated with heart defects
What is Branchio Oto Renal Syndrome?
Something to consider if your patient has dysmorphic ears
What is hypertelorism? Hypotelorism?
Hypertelorism is eyes being set too far apart; hypotelorism is too close
- Normal distance between eyes should be equal to width of 1 eye
What is telecanthus?
Inner canthal distance is much closer to interpupillary distance than it should be (?)
What to consider with Waardenburg syndrome?
- Did patient pass the newborn hearing screen?
- Is your patient’s speech and language on target?
- May have heterochromia
What is seen here?
- Close-set eyes
- Cleft
- Not much midface
This indicates holoprosencephaly
- Trisomy 13
- Pt could have a translocation (if so, one parent could be a translocation carrier and this may affect subsequent births)
Describe these palpebral fissures
- Left: downslanting palpebral fissures (Noonan syndrome)
- Right: upslanting palpebral fissures (Down syndrome)
What are the abnormalities seen in these eyes? What are the associated syndromes/clinical features?
- Top left: Coloboma
- Top right: Lisch nodules (neurofibromatosis)
- Bottom left: heterochromia (Waardenburg’s syndrome; hearing loss)
- Bottom right: Brushfield spots (Down’s syndrome)
What ocular abnormalities are seen here?
What are the associated diseases/clinical features?
- Top left: Epibulbar dermoid (Goldenhar syndrome)
- Top right: slate-grey sclera (Osteogenesis imperfecta)
- Bottom: leukocoria (retinoblastoma)
What is seen here? Seen in what condition?
Tubular nose
- May be seen in Velocardiofacial syndrome (del22q11.2); look for family history
What is seen here?
Seen in what condition?
Anteverted nares
- May be seen in Smith-Lemli-Opitz syndrome (AR)
What conditions are associated with mouth, philtrum, and chin changes?
- Prader-Willi Syndrome (short philtrum?)
- Cornelia de Lange Syndrome
- Fetal alcohol syndrome (long, smooth philtrum; thin upper lip)
- Fragile X syndrome (big chin)
Types of cleft lip?
- Unilateral incomplete
- Unilateral complete
- Bilateral complete
Types of cleft palate?
- Incomplete cleft palate
- Unilateral complete lip and palate
- Bilateral complete lip and palate
If cleft palate + micrognathia (small chin), think of what?
Stickler syndrome (AD)
If cleft palate + micrognathia + antiverted nares, think what?
Smith Lemli Opitz syndrome (AR)
if cleft palate + tubular nose + small ears, think what?
Deletion 22q11.2 (Velocardiofacial syndrome?)
If cleft palate + holoprosencephaly, think what?
Heterogeneous etiology
What else should be considered if tongue is very large?
If pt is hyoglycemic
What should be considered in pt with a bifid uvula?
Pt could have aortic dissection
(Loeys Dietz syndrome)
Broad necks are seen in what conditions?
What medical co-morbidities should be considered?
- Turner’s syndrome (45X) with coarctation of the aorta
- Noonan’s syndrome with pulmonic stenosis
What is clinodactyly?
Curved finger (folds are not parallel) because bone is wedge-shaped
- Seen commonly in Down syndrome
Another feature you may see in the hand of someone with Down syndrome?
Single transverse palmar crease
What is syndactyly?
Missing/fused digits (?)
What is polydactyly?
Abnormally many number of digits
What is oligodactyly?
Abnormally fewer number of digits
Other dactylies…
What causes this?
Amniotic bands
What is seen here?
Club feet (foot unable to be placed flat on floor)
What is seen here?
Rocker-Bottom foot (seen in trisomy 13?)
Examples of ‘Normal Variants’ on Exam
(features that occur in >4% of the population)
Common examples
• Stork bite mark in infants
• Mild 2-3 syndactyly of toes in infants
• Shallow sacral dimple
• Darwinian tubercle of the ear helix
• Incompletely over folded helix in infants
• Brushfield spots of the iris in newborns (20% nl newborns)
• Central post hair whorl (14%)
• Mild frontal upsweep of the hair (5%)
Key Exam Findings for Specific Neurogenetic Conditions:
1) . Fragile X syndrome
2) Tuberous Sclerosis
3) Timothy Syndrome
4) Sotos Syndrome
5) PTEN mutations
6) Moebius syndrome
1) Fragile X syndrome – macrocephaly, ligamentous laxity, macro-orchidism
2) Tuberous Sclerosis – facial fibrous angiomatous lesions (adenoma sebaceum),
hypopigmented macules including ash leaf spots and confetti hypopigmentation,
shagreen patches/orange peel spots, periungual fibromas. Requires a Woods lamp.
3) Timothy Syndrome – finger syndactyly,
4) Sotos Syndrome – macrocephaly, broad forehead, large hands and feet
5) PTEN mutations – pigmented nevi on the penis or scrotum
6) Moebius syndrome – facial weakness making it impossible to smile, usually
asymmetric. Inability to fully abduct the eye (all the way laterally)
Hair Dysmorphology
Name 4 Abnormalities:
Hair Dysmorphology
Abnormalities:
1. Multiple Hair Whorls: Multiple hair whorls, widely spaced (>3cm) double hair whorls, markedly displaced hair whorls or no posterior hair whorl are abnormal.
-A central hair whorl which occurs in 5% is a normal variant
- *2. A frontal cowlick** is an accessory hair whorl and though relatively common it indicates a subtle alteration in fetal brain growth. A marked upsweep, especially in conjunction with other hair growth pattern abnormalities is abnormal.
- *3. A low anterior hairline** especially approaching the lateral eyebrows is abnormal.
4. A widow’s peak is seen in patients with hypertelorism and reflects a lack of hair suppression around the eyes as they are laterally displaced. A marked widow’s peak is abnormal.
5. Upsweeps of the posterior hair line or slightly low posterior hair lines are common and if not pronounced are considered normal variants.
Face Dysmorphology:
1) Asymmetric face
2) Flat face
3) Mid-face hypoplasia
4) Flat malar region
5) Triangular face
6) Prognathism/prominent mandible Prognathism is characteristic of Sotos syndrome which is an autism related disorder.
7) Micrognathia/small mandible.
8) A dimpled, grooved or markedly pointed chin is abnormal.
9) Coarse features are age and gender dependent. Coarse facial features make young children appear old for their age.
1) Asymmetric face is a frequent feature in dysmorphology syndromes but can also be part of a neurologic or muscle disease. It is often not noted until you ask the child to smile. Being alert to facial asymmetry will help identify Moebius syndrome.
2) Flat face is best judged from the side where the plane of the face and features are all in a straight line.
3) Mid-face hypoplasia is due to an underdeveloped maxilla. It gives a dished-in face.
4) Flat malar region is similar and often misclassified as midface hypoplasia. It is due to underdevelopment of the zygoma.
5) Triangular face exhibits disparity between the broad forehead and narrow jaw to give a pixie look.
6) Prognathism/prominent mandible is usually easy to spot. It is often familial. Prognathism is characteristic of Sotos syndrome which is an autism related disorder.
7) Micrognathia/small mandible. Mandible is recessed and is sometimes associated with a midline submucous cleft of the palate. The association between micrognathia, a midline cleft palate and glossoptosis is called Pierre Robin sequence.
8) A dimpled, grooved or markedly pointed chin is abnormal.
9) Coarse features are age and gender dependent. Coarse facial features make young children appear old for their age.
