Practical 2 - Foetal Malformations Flashcards

Question

What is amelia

Answer 1

Absence of one or more of the extremities

Answer 2

Presence of extra fingers or toes - extra digits frequently lack proper muscle connections - Usually biltaeral (Absence of a digit (ectrodactyly) occurs unilaterally

Answer 3

Abnormal cleft between the second and fourth metacarpal bones and soft tissues Third metacarpal and phalangeal bones are almost always absent Thumb and index finger may be fused

Answer 4

Two or more fingers or toes are fused -mesenchyme between prospective digits do not undergo the normal apoptosis to make discrete digits

Answer 5

``` Radiation* Infection Thalidomide Pesticide and insecticide exposure Maternal smoking ```

Answer 6

Amniotic bands - adhesions between amnion and affected structures in the foetus - cause ring constriction - Amputations of limb or digits - origin unclear

Answer 7

Skeletal dysplasia caused by abnormal cartilage development | - may be caused by a number of genetic mutations that can be inherited

Answer 8

1/20,000 Long bones - shortening of proximal limbs Megalocephaly Small midface Short fingers Autosomal dominant 90% sporadic FGF 3 receptor mutation

Answer 9

Start parallel to cranial-caudal axis Rotates 90 degrees clockwise around longitudinal axis - left -> anterior, right -> posteriro Further growth -> rotation AP axis --> pylorus moves right

Answer 10

``` 1/1000 Signs occur between 3-5 weeks Projectile vomit Unaffected appetite Signs of dehydrations Fewer full nappies FTT ``` Genetic component Boys>Girls

Answer 11

Rapid elongation of the gut and its mesentry form the primary intenstinal loop 6th week - the intestinal loops become too big for the abdo cavity Enter extraembryonic cavity in umbilical cord 10th week intestinal loops begin to return

Answer 12

Herniation of abdo viscera through enlarged umbilical ring (viscera covered by amnion) Failure of bowel to return to body cavity during physiological herniation

Answer 13

1/4,000 USS Also combined test 20 weeks (AFP)

Answer 14

``` High mortality (25%) Severe malformations -cardiac (50%) -NTD (40%) -Chromosomal abnormalities (15%) ```

Answer 15

Protrusion of abdo contents through body wall directly into amniotic cavity Lateral to umbilicus Abnormal closure of body wall around connecting stalk Viscera not covered by peritoneum or amnion -bowel may be damaged due to exposure to amniotic fluid

Answer 16

1/2000 Frequency is increasing, especially among young women Not associated with chromosome abnormalities or other severe defects

Answer 17

90% Survival rate excellent (Volvulus resulting in compromised blood supply may cause large areas of necrosis and lead to death)

Answer 18

Pronephros - rudimentary-non-functional - disappeared by 4th week Mesonephros - develops 4th week - may function for a time Metanephros - Forms definitive kidney - starts to develop 5th week

Answer 19

Nephrons -outgrowth of mesonephric duct close to entrance to cloaca - bud penetrates metanephric tissue, which is moulded over its distal end - bud dilates -> primitve renal pelvis and splits into cranial and caudal portions (major and minor calyces) Nephrons Collecting ducts Renal pelvis Major and minor calyces

Answer 20

Numerous cysts form in collecting ducts Dominant and recessive variants Both linked to mutations in genes encoding cilia proteins

Answer 21

Renal failure -recessive (1/5000) - infancy -dominant - later

Answer 22

1/600 Kidneys pushed so close together during ascent through arterial fork, fuse inferior mesenteric artery prevents ascent - lower level

Answer 23

early splitting of ureteric bud Partial or complete splitting May each have its own renal pelvis and metanephric tissue -more commonly share lobules

Answer 24

derive from persistence of embryonic vessels formed during ascent of kidney usually arise form aorta and enter pole of kidney

Answer 25

Sex determining region on Y (SRY) gene Transcribes testis-determining-factor In its presence, male development occurs

Answer 26

First appear - genital ridges = epithelium w/ underlying mesenchyme Primordial germ cells migrate 5th week Invade genital ridges 6th week Ridges proliferate --> primitive sex cords Indifferent gonads

Answer 27

Gonads don't develop

Answer 28

Mesonephric (Wolffian) | Paramesonephric (Mullerian)

Answer 29

SRY & SOX9 --> antimullerian hormone SRY upregulates -steroidogenesis factor (SF1) -stimulates sertoli and leydig cell SF1 & SOX9 increase AMH concentration Regression of mullerian duct Leydig cells produce testosterone Converted to dihydrotestosterone in target tissues Virilisation of wolffian duct

Answer 30

Not cranial epididymis | Main genital ducts epidymis --> seminal vesicles

Answer 31

Incomplete urethral fold fusion - abnormal openings of the uerethra, usually inferior aspect - usually near flans, along shaft or near base of penis Rarely, urethral meatus along scrotal raphe If fusion fails entirely, wide sagittal slit along length of penis and scrotum - scrotum resembles labia majora

Answer 32

3-5/1000 Incidence has doubled over 15-20 years

Answer 33

1/30,000 Urethral meatus found on dorsum of penis Often associated with exstrophy of the bladder and abnormal closure of ventral body wall

Answer 34

Abdominal contents herniate throught the inguinal canal into the scrotum

Answer 35

A portion of endoderm lined yolk sac cavity is incorporated into embyro --> primtive gut Yolk sac and allantois remain extra-embryonic

Answer 36

Retinoic acid concentration gradient - pharynx - low - colon - high Stomach: SOX2 Duodenum: PFX1 Hindgut: CDXA

Answer 37

Celiac Superior mesenteric Inferior mesenteric

Answer 38

1/2000-1/4000 Fistula between oesphagus and trachea - can be a one just drain into trachea OR -Can drain into trachea, then drain out of trachea more distally

Answer 39

``` • Symptoms: o Frothy, white bubbles in the mouth o Coughing or choking when feeding o Vomiting o Blue colour of skin, especially when feeding o SOB • Complications o Aspiration o Pneumonia o Asphyxiation ```

Answer 40

exogenous sex hormones Alcohol Working in argiculture VACTERL

Answer 41

• WNT4 is the ovary-determining gene --> This gene upregulates DAX1 --> Inhibits the function of SOX9 (which upregulates Anti-mullerian hormone)

Answer 42

* Uterine tubes, uterus, cervix and upper vagina. | * Oestrogens.

Answer 43

does what is says on the tin

Answer 44

First arch abnormalities 1/40,000-1/70,000 Symptoms - Zygmatic hypoplasia - Mandibular hypoplasia - Downslanting palpebral fissures - lower eyelid colobomas - external ear malformation - Autosomal dominanet

Answer 45

1/4000 Microdeletion chromosome 11 Absent thymus and parathyroids ``` Immune defiency Cardiac anomalies Mild facial dysmorphology -shortened philtrum -low set ears -nasal clefts ``` learning disabilities

Answer 46

Incisive foramen anterior - cleft tip, cleft jaw, cleft between primary and secondary palates Posterior - cleft secondary palate - cleft uvular - defective growth of lateral palatal processes

Answer 47

unilateral -maxillary prominence fails to fuse with merged medial nasal prominences Bilateral - failure of both maxillary prominences to fuse with merged medial nasal prominences

Answer 48

1/700 - 1/1000 Male>Female Aetiology - syndromic - genetic - non syndromic (70% CLP, 50% CPO) - Teratogen - benzos, rubella

Answer 49

intermaxillary segment fuse with palatine process -primary palate Fusion of palatine processes - secondary palate - palatine raphe

Answer 50

Failure of normal growth of palatal shelves Failure of fusion of palatal shelves Obstruction of palate fusion by tongue Failure of shelve to rise above the tongue

Answer 51

``` Difficulty feeding Aspiration pneumonia Speech and Hearing Dental problems Cosmesis ```

Answer 52

Johannsson and Ringsberg - cleft palate can be emotionally traumatic to parents - one of most common congenital malformations - otitis media common complciation - more severe clefting has more severe social implications

Answer 53

Facial prominences appear at the end of week 4 around the stomodeum - frontonasal prominence - maxillary prominence - mandibular prominence Nasal placode invaginate in 5th week to form nasal pits and nasal prominences (medial and lateral) Maxillary prominences grow larger and medially Pushes nasal prominences towards midline, medial prominences fuse Maxillary prominences fuse with medial nasal prominence

Answer 54

formed from fusion of two medial nasal prominences 3 parts - Labial - philtrum - Upper jaw - four incisors - Palatal - froms primary palate

Answer 55

Maxillary prominence separated from lateral nasal prominence by nasolacrimal groove Endoderm in the floor thickens to form a cord , detaches and canalises