Topic 5 Part 6 Child genetic health assessment

Question 1

_ is a necessary prerequisite for prognosis, plan of management and genetic counseling.

Answer 1

Accurate diagnosis.

Question 2

Congenital anomalies

Answer 2

1. Occur in 5-15% of newborns.

2. Examples: Heart defects, polydactyly.

Question 3

Teratogenic disorders

Answer 3

1. Occur in 1% of newborns.

2. Example: Fetal alcohol syndrome.

Question 4

Single gene disorders

Answer 4

1. Occur in 1% of newborns.

2. Examples: Cystic fibrosis, achondroplasia.

Question 5

Metabolic defects

Answer 5

1. Occur in 0.5% of newborns.

2. Example: Hurler syndrome.

Question 6

Chromosomal disorders

Answer 6

1. Occur in less than 1% of newborns.

2. Example: Down syndrome.

Question 7

Consanguineous matings are at higher risk for producing _ conditions.

Answer 7

Autosomal recessive.

Question 8

Family history components

Answer 8

1. Drawing the pedigree.
2. Asking about: Birth defects; functional problems; spontaneous abortions, infertility, and stillbirths; ethnicity; consanguinity; drug, alcohol, and medication use during pregnancy; maternal medical illnesses; maternal and paternal ages at the time of conception.

Question 9

“Rule of 6s”

Answer 9

60% of first trimester spontaneous abortions, 6% of stillborn babies, and 0.6% of liveborn babies have a cytogenetic aberration.

Question 10

Older maternal age increases the risk for _ in a fetus.

Answer 10

Cytogenetic disorders.

Question 11

Older paternal age increases the risk for _ in a fetus.

Answer 11

Single gene (autosomal dominant) disorders.

Question 12

Structural anomalies

Answer 12

Visible anomalies ranging from mild to severe; e.g., hypertelorism, anencephaly.

Question 13

Functional anomalies

Answer 13

Not necessarily visible and may not be obvious at birth; e.g., mental retardation, growth disorders.

Question 14

Dysmorphology

Answer 14

1. Physical examination for minor anomalies or atypical features, based on an established set of average human features.
2. Aptitude for dysmorphology requires recognizing the familiar as well as the unfamiliar.

Question 15

Dysmorphology is useful for the diagnosis of _

Answer 15

Williams syndrome, fragile X syndrome, Prader-Willi syndrome, Cornelia de Lange syndrome, mucopolysaccharidosis.

Question 16

Facial features measured in dysmorphology

Answer 16

Head circumference (micro- or macrocephaly), biparietal diameter, inner/outer canthus distance (hypo- or hypertelorism), philtral length, mouth width, ear length (also placement and rotation).

Question 17

Hypertelorism and downslanting palpebral fissures are associated with _

Answer 17

Micrognathia (small jaw).

Question 18

Hypotelorism is associated with _

Answer 18

Forebrain anomalies (holoprosencephaly).

Question 19

Brushfield spots in the iris, epicanthal folds, and upslanting palpebral fissures are associated with _

Answer 19

Down syndrome.

Question 20

Hand features measured in dysmorphology

Answer 20

Middle finger length, palm length, transverse creases, phalangeal creases, longitudinal radial crease.

Question 21

Clinodactyly

Answer 21

An abnormally curved finger, usually the fifth digit (pinky).

Question 22

Arachnodactyly

Answer 22

Long, thin fingers; associated with Marfan syndrome.

Question 23

Single transverse palmar crease

Answer 23

Associated with Down syndrome, but only 50% of Down syndrome individuals have it.

Question 24

Syndactyly

Answer 24

Abnormal linkages between fingers or toes; fairly common.

Question 25

Polydactyly

Answer 25

*Autosomal dominant* condition of extra digits.

Question 26

Sandle-gap toes

Answer 26

Associated with *Down syndrome*.

Question 27

If *3 or more* dysmorphic defects are present, the likelihood of an underlying _ is 90%.

Answer 27

Genetic syndrome.

Question 28

Syndrome

Answer 28

A *constellation* of features or symptoms that present together in a particular pattern due to a common cause.

Question 29

A child with obesity, brachydactyly (short hands and fingers), and hypoplastic gonads likely has _

Answer 29

Prader-Willi syndrome.

Question 30

A child with mental retardation, microcephaly, short palpebral fissures, low set ears, and epicanthal folds likely has _

Answer 30

Fetal alcohol syndrome.

Question 31

The vast majority of disorders tested in the newborn screening panel are _

Answer 31

Inborn errors of metabolism - defects of metabolic enzyme(s) whose function is energy production and consumption. Typically these have an *autosomal recessive* inheritance.

Question 32

Clinical findings in inborn errors of metabolism are often _

Answer 32

Nonspecific, variable, and confusable with *sepsis*.

Question 33

The only two disorders that *all* states screen for at birth

Answer 33

Phenylketonuria (PKU) and hypothyroidism.