Development and Genetic Disease

Question 1

What is charted at each well-child check?

Answer 1

Height, weight and head circumference

Question 2

Head circumference

Answer 2

Measured routinely in the first 2 years. If high, it may indicate hyrdocephalus or tumor. If low, it can point to microcephaly (TORCH)

Question 3

Height and weight

Answer 3

Measured routinely until adulthood. The pattern of growth is more important than the raw numbers. Infants may lose 5-10% of birth weight over the first few days but should return to BW by 14d.

Infants can be expected to double their BW by 4-5mo.

Triple it by 1y.

Quadruple by 2y.

Question 4

FTT

Answer 4

Persistent weight less than the fifth percentile for age or falling off the growth curve (crossing 2 major percentile lines on a growth chart)

1) Organic - due to an underlying medical condition like CF, congenital heart disease, celiac sprue, pyloric stenosis, chronic infection (HIV), GERD
2) Nonorganic - primarily due to psychosocial factors like maternal depression, neglect or abuse

Infants will fall off the weight curve first. Then height. Then head circumference.

Also important to take careful dietary history and closely observe maternal-infant interactions (esp preparation of formula and feeding)

Children should be hospitalized if there is evidence of neglect or severe malnourishment. Calorie counts and supplemental nutrition are mainstays of treatment

Question 5

How do you judge milestones of premature infants?

Answer 5

For premature infants less than 2 years old, chronological age is adjusted for gestational age. If infant born at 7 months gestation, they would be expected to perform at the 4 month level at a chronological age of 6 months.

Question 6

Gross motor milestones

Answer 6

1) 2m: Lifts head/chest when prone
2) 4-5m: Rolls front to back, back to front (4)
3) 6m: Sits on own
4) 9-10m: Crawls; pulls to stand
5) 12m: Walks alone; throws object
6) 2y: Walks up/down steps
7) 3y: Rides tricycle; climbs stairs with alternating feet (3-4y)
8) 4y: Hops
9) 5y: Skips; walks backward for long distances

Question 7

Fine motor milestones

Answer 7

1) 2m: Tracks past midline
2) 4-5m: Grasps rattle
3) 6m: Transfers objects; shows raking grasp
4) 9-10m: Uses 3 finger pincer grasp
5) 12m: Uses 2 finger pincer grasp
6) 2y: Builds tower of 6 cubes
7) 3y: Copies a circle;* uses utensils
8) 4y: Copies a cross* (square at 4.5y)
9) 5y: Copies a triangle,* ties shoelaces; knows L from R; prints letters

Question 8

Language milestones

Answer 8

1) 2m: Alerts to sound; coos
2) 4-5m: Laughs and squeals, orients to voice, begins to make consonant sounds
3) 6m: Babbles
4) 9-10m: Says mama/dada (nonspecific), says first word at 11m.
5) 12m: 1-3 words, 1 step command (15m is 5words, 18m is 8 words)
6) 2y: 2-word phrases, 2 step commands
7) 3y: 3 word sentences*
8) 4y: Knows colors and some numbers
9) 5y: Uses 5 word sentences*

Question 9

Social/Cognitive milestones

Answer 9

1) 2m: Recognizes parent; exhibits social smile*
2) 4-5m: Enjoys looking around; laughs
3) 6m: Demonstrates stranger anxiety*
4) 9-10m: Waves bye, plays pat-a-cake
5) 12m: Imitates actions; exhibits separation anxiety*
6) 2y: Follows 2 step commands*, removes clothes
7) 3y: Brushes teeth with help; washes/dries hands
8) 4y: Exhibits cooperative play; plays board games
9) 5y: Exhibits domestic role playing; plays dress-up

Question 10

Signs of autism

Answer 10

No babbling and/or gesturing by 12m

No single words by 16m

No 2-word phrases by 24m

Failure to make eye contact, and other signs of deficits in language or social skills

Question 11

Tanner staging

Answer 11

Performed to assess sexual development in boys and girls

Stage 1 - preadolescent

Stage 5 - adult

Increasing stages are assigned for testicular and penile growth in boys and breast growth in girls; pubic hair development is used for both stages

Question 12

Avg age of puberty

Answer 12

Boys - 11.5y. Precocious is 9y. Delayed is 14y.

Girls - 10.5y (menarche is 12.5y). Precocious is 8y. Delayed is 13.

Question 13

Normal sexual development

Answer 13

1) Boys - gonadarche (testes enlarge) then pubarche (pubic hair) then adrenarche (axillary and facial hair, voice) then finally growth spurt.
2) Girls - Thelarche (breast buds) then pubarche then growth spurt then menarche

Question 14

Precocious puberty

Answer 14

Any sign of secondary sex maturation in girls less than 8 or boys less than 9.

Often idiopathic, may be central or peripheral

Question 15

Delayed puberty

Answer 15

No testicular enlargement by age 14 or no breast development or pubic hair in a girl before age 13.

Question 16

Constitutional growth delay

Answer 16

A normal variant, and the most common cause of delayed puberty. The growth curve lags behind others of the same age but is consistent. There is often positive FHx and children catch up and ultimately achieve target height potential

Question 17

Pathological puberty delay

Answer 17

Rarely, due to systemic disease (IBD), malnutrition (anorexia), gonadal dysgenesis (Klinefelters, Turner) or endocrine abnormalities (hypopituitarism, hypothyroidism, Kallman’s, androgen insensitivity, Prader-Willi)

Question 18

Down Syndrome

Answer 18

1) Genetics - Meiotic nondisjunction (95%), robertsonian translocation (4%) or mosaicism (1%)

2) Features
a) Most common chromosomal disorder and cause of mental retardation. Associated with advanced maternal age

b) Presents with mental retardation, flat facial profile, upslanted eyes with epicanthal folds, simian crease, general hypotonia, atlantoaxial instability, and extra neck folds (nuchal folds are sometimes seen on prenatal US)
c) Associated with duodenal atresia, Hirschsprung, congenital heart disease. The most common malformation is AV canal (60%); ASD, VSD and PDAs (20%); and complex congenital heart disease
d) Also associated with higher risk of ALL, hypothyroid and early-onset Alzheimer’s

Question 19

Edward’s Syndrome

Answer 19

1) Trisomy 18
2) Presents with severe mental retardation, rocker bottom feet, low-set ears, micrognathia, clenched hands (overlapping fourth and fifth digits) and a prominent occiput
3) Associated with congenital heart disease. May have horseshoe kidneys. Death usually occurs within 1 year of life

Question 20

Patau’s Syndrome

Answer 20

1) Trisomy 13
2) Presents with severe tardation, microphthalmia, microcephaly, cleft lip/palate, holoprosencephaly, punched out scalp lesions, polydactyly, and omphalocele
3) Associated with congenital heart disease
4) Death usually within 1 year of birth

Question 21

Klinefelter’s Syndrome (male)

Answer 21

1) 47 XXY
2) Characterized by presence of inactivated X (Barr body)
3) Associated with advanced maternal age
4) One of the most common causes of hypogonadism in males
5) Presents with testicular atrophy, a eunuchoid body shape, tall stature, long extremities, gynecomastia, female hair distribution
6) Treat with testosterone (prevents gynecomastia; improves secondary sex characteristics)

Question 22

Turner’s Syndrome (female)

Answer 22

1) 45 XO
2) Missing 1 X chromosome. No Barr body
3) Most common cause of primary amenorrhea. Due to ovarian dysgenesis (reduced estrogen)
4) Features include short stature, shield chest, widely spaced nipples, webbed neck, coarctation of aorta (reduced femoral pulses) and/or bicuspid aortic valve. May present with lymphedema of hands and feet in neonatal period. May have horseshoe kidney

Question 23

Double Y males

Answer 23

1) 47 XYY
2) Observed with higher frequency among inmates in jail
3) Phenotypically normal; patients are very tall with severe acne and antisocial behavior (seen in 1-2% of XYY males)

Question 24

PKU

Answer 24

1) Auto recessive, low phenylalanine hydroxylase or low tetrahydrobiopterin cofactor
2) Tyrosine becomes essential and phenylaline builds up excess phenyl ketones.
3) Screened for at birth
4) Normal at birth; presents within first few months of life
5) Presents with mental retardation, fair hair and skin, eczema, blond hair, blue eyes, and a musty urine odor
6) Associated with increased risk of heart disease
7) Modify diet by decreasing phenyalaline (artificial sweeteners) and increasing tyrosine. A mother with PKU who wants to become pregnant must first restrict her diet as above before conception

Question 25

Fragile X

Answer 25

1) X-linked dominant defect affecting the methylation and expression of FMR1 gene
2) Second most common cause of genetic mental retardation
3) Presents with large jaw, testes and ears and with autistic behaviors
4) A triplet repeat disorder that may show genetic anticipation

Question 26

Fabry’s

Answer 26

1) LSD
2) Caused by deficiency of a-galactosidaseA that leads to accumulation of ceramide trihexoside in heart, brain and kidneys
3) First sign is severe neuropathic limb pain. Also presents with joint swelling
4) Skin involvement takes the form of angiokeratomas and telangiectasias
5) Findings include renal failure and a higher risk of stroke and MI (thromboembolic events)
6) X-linked recessive

Question 27

Krabbe’s

Answer 27

1) LSD
2) Absence of galactosylceramide and galactoside (due to galactosylceramidase deficiency), leading to accumulation of galactocerebroside in brain
3) Characterized by progressive CNS degeneration, optic atrophy, spasticity, and death within first 3 years of life
4) Auto recessive

Question 28

Gaucher’s

Answer 28

1) LSD
2) Caused by deficiency of glucocerebrosidase that leads to accumulation of glucocerebroside in brain, liver, spleen and bone marrow
3) Gaucher cells have a crinkled paper appearance with enlarged cytoplasm
4) May present with anemia and thrombocytopenia
5) Infantile form results in early, rapid neuro decline. Adult form (more common) is compatible with normal life span and does not affect brain
6) Auto recessive

Question 29

Niemann-Pick

Answer 29

1) LSD
2) Deficiency in sphingomyelinase that leads to buildup of sphingomyelin cholesterol in reticuloendothelial and parenchymal cells and tissues
3) Patients with type A die by age 3
4) May have cherry-red spot and hepatosplenomegaly
5) Auto recessive
6) Pick nose with sphinger

Question 30

Tay-Sachs

Answer 30

1) LSD
2) Absence of hexosaminidase that leads to GM2 ganglioside accumulation
3) Infants may appear normal until 3-6m, when weakness begins and development slows and regresses. An exaggerated startle response may be seen
4) Death by age 3
5) Presents with cherry-red spot but NO HSM
6) Carrier rate is 1 in 30 jews of european descent (1 in 300 for others)
7) Tay-SaX loves heXosaminidase

Question 31

Metachromatic leukodystrophy

Answer 31

1) LSD
2) Deficiency of arylsulfatase A that leads to accumulation of sulfatide in brain, liver, kidney, and peripheral nerves
3) Demyelination leads to progressive ataxia and dementia
4) Auto recessive

Question 32

Hurler’s Synrome

Answer 32

1) LSD
2) Deficiency of a-L-iduronidase
3) Leads to corneal clouding, mental retardation, and gargoylism
4) Auto recessive

Question 33

Hunter’s Syndrome

Answer 33

1) LSD
2) A deficiency of iduronate sulfatase
3) A mild form of Hurler’s with no corneal clouding and mild retardation,
4) X recessive
5) Hunters need to see (no corneal clouding) to aim for the X

Question 34

CF general

Answer 34

Auto recessive disorder caused by mutations in CFTR gene (chloride channel) on chromosome 7 and characterized by widespread exocrine gland dysfunction.

CF is the most common severe genetic disease in USA and is most frequently found in Caucasians

Question 35

History and physical for CF

Answer 35

1) Half of patients present with FTT or chronic sinopulmonary disease
2) Characterized by recurrent pulmonary infections (especially with pseudomonas and S aureus) with subsequent cyanosis, digital clubbing, chronic cough (most common pulm sx), dyspnea, bronchiectasis, hemoptysis, chronic sinusitis, rhonchii, rales, hyperresonance to percussion, and nasal polyposis
3) 15% of infants present with meconium ileus (almost all cases of meconium ileus are due to CF). Patients usually have greasy stools and flatulence; other prominent GI symptoms include pancreatitis, rectal prolapse, hypoproteinemia, biliary cirrhosis, jaundice, and esophageal varices
4) GI symptoms are more prominent in infancy; pulmonary manifestations predominate thereafter
5) Additional Sx include type 2 DM, salty tasting skin, male infertility (agenesis of vas defrens) and unexplained hyponatremia
6) Patients are at risk for fat-soluble vitamin deficiencies secondary to malabsorption and may present with manifestations of these deficiencies

Question 36

Dx of CF

Answer 36

1) Diagnosed by sweat chloride test greater than 60 in those less than 20 years of age and more than 80 in adults
2) Confirmed by genetic testing
3) ABG shows hypochloremic alkalosis in severe cases
4) Most states now perform mandatory newborn screening, but occasional false positives occur, so children must be brought in for a sweat test to distinguish disease from carrier states.

Question 37

Tx of CF

Answer 37

1) Pulm manifestations managed with chest PT, bronchodilators, corticosteroids, antibiotics (should cover psuedomonas) and DNase
2) Administer pancreatic enzymes and fat soluble vitamins (KADE) for malabsorption
3) Nutritional counseling and support with high calorie and high protein diet are essential for health maintenance
4) Patients who have severe disease but can tolerate surgery may be candidates for lung or pancreas transplants. Life expectancy was once about 20, but now past 30.