Genetics

1

Dysmorphology

Phenotypic features which when present in combination suggest the presence of chromosomal abnormalities ( numerical or structural ).

Head and CNS

Microcephaly

Macrocephaly.

“Setting sun”

sign

Increased intracranial

pressure may result from

hydrocephalus

subdural hematoma. It

can occur in parenchymal

or midbrain lesions,

especially kernicterus.

Hydranencephalyfailure of the

development of

the cerebrum with

resulting gross dilatation

of the ventricles

Dandy-Walker

malformationa cyst-like dilation of the fourth

ventricle,

an abnormal cerebellar vermis,

elevation of the tentorium

cerebelli and lateral and

transverse sinuses and torcula

(torcular Herophilli),

lack of patency of the foramina

of Magendie and Luschka,

enlargement of the posterior

fossa,

hydrocephalus.

• lacunar skull

(lückenschädel):

defective calcification

of the skull bones

associated with neural

tube defects

(encephalocele and

meningocele).

Neural tube defects

• Anencephaly

Craniorachischisis

Encephaloceles

bony

defects of the skull with

protrusion

of the meninges which

may contain neural

tissue.

They are most common

in the

occipital area.

Floppy infant

Congenital parietal

foramina

Normal sutures

• Dolichocephaly :

sagittal suture remains

open.

Common in preterms.

• Scaphocephaly:

Premature fusion

of the sagittal

suture

Brachycephaly:

premature

fusion of the

coronal sutures

• Trigonocephalyis due to

premature fusion

of the metopic

suture and is

represented

clinically by a

triangular-shaped

head

Plagiocephaly (oblique-

shaped skull) occurs with

premature fusion of a

single suture (such as the

coronal or lambdoidal) or

with a congenital postural

deformity

Kleeblattschädel

(“cloverleaf ”skull) is

the result of premature

fusion of the sagittal and

coronal sutures. There is

a trilobed appearance of

the skull with indentations

in the center and in the

temporal regions.

Carpenter’s syndrome

(acrocephalopolysynd

actyly) high steep

protruding forehead,

turribrachycephaly due

to fused coronal

sutures, the flat midface,

the small pinched nose,

and the downward

slanting of the palpebral

fissures.

• Prominent occiput.

• Cutis aplasia

congenita:Associated with

embryologic

malformations such as

meningomyelocele

and spinal dysraphia,

omphalocele, and

gastroschisis.

Ears

Ears

• Small or

large.

• Malformed.

• Low set ears

• Transverse

crease.

• Tags

MicrotiaHypoplasia of the pinna

associated with atresia of

the external auditory canal

Otocephaly

Bow- tie shaped due to branchial

arch embryopathy resulting in

agnathia, microstomia, and small

posteriorly positioned hypoplastic

tongue. The ears are very low set

and the lower lobes may be fused to

the neck which was short and thin.

Aural ascent does not occur due to

the lack of development of the jaw,

hence the low position of the ears.

These infants typically have

hypoplastic lungs.

Eyes

• Upward or

downward slanting

of the palpebral

fissures .

• Hypertelorism

(Telecanthus ).

• Epicanthal folds.

• Synophrys .

• Congenital glucoma.

• Congenital cataract.

Retinoblastoma

Brushfield eyes

brown irides

which are

pathognomonic

for Down

syndrome

Subconjunctival

hemorrhagesresolve

spontaneously

without any

consequences.

Dacryocystocele

may occur as an autosomal

dominant in families

The lacrimal sac is blocked

at both ends and a

sterile swelling appears as

a purplish swelling adjacent

to the base of the nose.

Simple lacrimal probing

allows

for a swift resolution of this

problem

Ankyloblepharon

filiforme adnatumfusion of the upper and

lower

eyelids by small filiform

attachments which can be

cut

with scissors.

Coloboma

Treacher-Collins

syndrome

Goldenhar’s

syndromehemifacial macrosomia, are

colobomas of the upper lids,

solid epibulbar dermoids

located at the inferotemporal

border of the cornea, and solid

lipodermoids

located in the superotemporal

sulcus near the lacrimal gland.

Oculoauriculovertebral

dysplasia is sporadic and the

basic defect is unknown.

Fraser’s

syndromeAn autosomal recessive

disorder which occurs

when the maturation of

the lids

is interrupted and the lid

folds fail to develop. This

infant shows complete

cryptophthalmos by the

left lid (surface ectoderm)

with complete coverage

of the corneal epithelium.

Congenital

entropion

inturning of

the lower nasal lid such

that the lashes irritate the

cornea.

Congenital

ectropionThe tarsal conjunctiva

is chemotic,

hyperemic,

and protrudes outward.

The lid returns to

normal a few

days following

application of

ophthalmic ointment

and moist

sterile gauze

dressings.

Exophthalmos

Neonatal

Hyperthyroidism,

craniofacial anomalies

and shallow

Orbits e.g: Crouzon's

syndrome

Aniridia

Autosomal dominant

absence of iris

also occurs

as a deletion syndrome

(del 11p13)

known as the WAGR

syndrome

(Wilms’ tumor, Aniridia,

Genitourinary

anomalies, and mental

Retardation).

Megalocornea

enlarged corneal

diameter present at

birth

intraocular pressure is

not

increased.

Heterochromia

Tuberous sclerosis,

waardenburg

syndrome

and normal individuals

Nose

• Depressed nasal

bridge.

Nasal cleft may occur

in otherwise

normal

infants.

• Peaked nose.

• Bulbous nose.

Philtrum.

Choanal atresiablockage of one or both

choanae and may present shortly after

birth with cyanosis which is

relieved when the infant cries.

unilateral in 90% of cases

more common in female

Associations

occur with facial anomaly syndromes such

as Apert’s and Treacher-

Collins, and with the CHARGE sequence

(coloboma, heart disease, atresia

of the choanae, retarded postnatal growth

and development, genitourinary

anomalies, and ear anomalies and

deafness).

Proboscis lateralisis a congenital

abnormality in which

the nose fails to

develop normally.

Median cleft syndrome

Cyclopia

superior proboscis

holoprosencephaly

Mouth

Lower jaw

• Retromicrognathia.

Mouth

• Cleft lip and palate.

Microstomia

may occur in normal

infants or is

associated with many

syndromes such as

Hallermann-Streiff

syndrome, Freeman-

Sheldon syndrome

and mosaic trisomy 8.

Macrostomia

may be unilateral or

bilateral and is associated

with deformities of the

outer ear, hypoplasia of

the mandible or maxilla,

and cleft palate.It is also

seen in Goldenhar’s

syndrome (unilateral

macrostomia,

antimongoloid slant to the

eyes, preauricular skin

tags, and deafness).

Eruption cysts in an

infant at birth

Natal teethlower incisors X-ray films

are needed

1. Predeciduous teeth.

They are usually loose,

and the roots are absent

or poorly formed.

Removal is necessary to

avoid aspiration.

2. True deciduous teeth.

These teeth are true teeth

that erupt early. They

should not be extracted.

Ellis-van Creveld

syndrome (chondroectodermal

dysplasia) defect in the

upper lip due to fusion

ofthe labiogingival

margins of the upper lip.

lip

Gum hypertrophy due to a mother

treated with

phenytoin during

pregnancy.

Epstein’s pearls

small cluster of whitish-

yellow swellings

at the junction of the soft

and hard

palate in the midline.

Bohn’s nodules

inclusion cysts on the

alveolar margin in this

infant.

Congenital epulis

a form of embryonal

hamartoma.

Tongue

• Macroglossia.

• It may be true or

pseudo.

Aglossia

hypoglossia

aglossia/hypoglossia

adactylia syndrome.

Hamartomatous

masses on tongueOrofaciodigital

syndrome, Type I

Neck

• Short webbed

neck.

Congenital midline

cervical cleft

failure of

the branchial arches to

fuse

in the midline. It most

commonly

affects females

Sternomastoid

tumorWhen delivery has

involved

excessive rotation or

gross lateral rotation of

the

neck, a lump may appear

in the sternomastoid

muscle

Branchial clefts

result in remnants, fistulae or

cysts. Defects are usually

unilateral and the external

opening lies at the anterior edge

of the

sternocleidomastoid muscle,

usually at the lower third.

Secondary

bacterial infection and cyst

formation may occur. In this

infant

there is a branchial cleft remnant

Cystic hygroma

(lymphangioma)

soft fluctuating

mass. consist of

proliferation of lymph

vessels.

Although not malignant,

they may spread over

the

neck with extension into

the mouth.

Hand

Hand

• Polydactyl

• Syndactyly

• Brachydactyly:

short broad hand

Camptodactylytrigger finger

• Clinodactyly

• Simian crease

• Clenched hand

Hypoplastic nails

Acheiria

Floating thumb

• Macrodactyly

Lobster-claw deformity (ectrodactyly, or split

hand/split foot

deformation).

Foot

Foot

• Talipus equinovarus

• Rocker bottom heel

• Polydactyly

Wide separation

between first and

second toes

limbs

Dislocation of the

hip:

common in

females

Congenital

absence of

patellae:in a normal infant. this

finding is also noted,

trisomy 8 and

Nievergelt syndrome.

limbs

• Amelia:

is absence of

the entire limb

structure

Phocomelia syndrome:more proximal portion of a

limb fails to develop

properly but distal

structures are relatively

intact.

Common with maternal

thalidomide ingestion

Sirenomelia

Caudal regression $

Absent radius:

TAR $

Fanconi

anemia

Arthrogryposis

multiplex congenita:

contractures, muscular

hypotonia,generalized

thickening of the skin

withdimpling, and hip

subluxation; and bilateral

talipes equinovarus,

opisthotonos and

scoliosis of the spine

Chest and abdomen

Asphyxiating

thoracic dystrophy

) Jeune's

syndrome(autosomal recessive

due to the short ribs results

in a small chest which limits

pulmonary expansion and

severely restricts respiration.

Because of the small thorax,

the whole liver lies in the

abdomen, producing the

rounded and enlarged

appearance.

Esophageal

atresia

Congenital

diaphragmatic

hernia

may lie in the hemithorax

during fetal life, resulting

in hypoplasia

of the lungs.

Ectopia cordis

Umbilical

granulomaovergrowth

of granulomatous tissue

at the umbilicus when the cord

separates. These occur more

commonly in infants with large,

thick umbilical cords. The tissue

may be friable and bleeds easily.

This can be treated with silver

nitrate cauterization. Infants

who have discharge or foul odor

at the umbilicus may have

umbilical granulomas or patent

vitellointestinal duct.

Omphalocelefailure of the complete return of

intestines to the abdominal cavity in

early fetal life (10 weeks). Extra-

abdominal contents are positioned

midline. The umbilical cord is

incorporated and a sac is present.

Intestinal malrotation is a frequent

associated finding. Omphaloceles

may occur as isolated findings or

can be associated with other

congenital and chromosomal

abnormalities. It is frequently seen

in trisomy 13 and in

Beckwith-Wiedemann syndrome.

Gastroschisis

anterior abdominal

wall defect which is usually

paramedian to the right of

the umbilical cord insertion.

there is no covering

membrane.

Prune

belly syndromeabsence of the abdominal

musculature

Ectopia vesica

119