The human genome consists of 46 homologous
chromosomes: 23 chromosomes from each parent. Down syndrome (DS), also
known as trisomy 21, is a prenatal genetic disorder caused by the
presence of an extra chromosome 21. Unlike abnormalities caused by the
exposure to teratogens, DS is related to maternal age; that is, the
older the mother, the higher the risk of producing an egg with
chromosomal abnormalities (Gelbert et al., 2002) (Figure 1).
Figure 1. The relationship between
maternal age and the likelihood of giving birth to a Down syndrome child
(Gelbert et al., 2002).
As Canada's population continues to increase,
teachers are beginning to see a progressively larger number of students
with genetic abnormalities in their classrooms. Because there is an
overlap in some of the physical characteristics observed in various
genetic defects, it is important for a teacher to accurately distinguish
between the different genetic disorder types. People with DS possess
short broad hands, short stature, and diminished muscle tone (Figure 2).
Combined with these physical defects, DS students are mentally
handicapped with an IQ in the 20 to 50 range (Gelbert et al.,
2002). There are no particular behavioural patterns unique to people
with DS, but they are likely to become frustrated or anxious more easily
than normal people (Alton, 2000). Most of their behaviour depends on how
they have been raised at home prior to schooling. Moreover, students
with DS may experiences problems with their speech and language,
auditory short-term memory, and motor coordination. They may also
possess a shorter concentration span and take longer learning the rules
of the classroom (Alton, 2000).
Figure 2. Characteristics of Down
syndrome (Gelbert et al., 2002).
Regardless of how old they become, these learning
difficulties are prominent throughout their lifetime. Therefore, it is
important for all teachers - whether it's preschool, K to 12, and even
adult school teachers to understand their student's unique struggles and
demands. Often, when a child with DS encounters difficulty coping with a
certain class activity, they will begin to show inappropriate classroom
behaviours, as they are naturally sensitive to failure (Johnson, 2004).
An elementary school teacher who is aware of these circumstances can
show greater recognition towards the student's failures and be more
encouraging and caring to keep the student on task; the teacher must
also avoid criticizing the child. Furthermore, a teacher can reassess
the lesson plan to ensure it is suitably differentiated to fit the needs
of all students; making sure it is not overexerting the DS student's
cognitive potential. Many students with DS know far more than they can
express in words (Johnson, 2004). A teacher teaching a student with DS
must teach the student to communicate in whatever way works and teach
the other students how to engage in the same manner when communicating
together. For instance, if a student cannot formulate the correct words,
a teacher can ask the student to use pictures, drawing, symbols, and
signs to demonstrate their understanding. This is an important method to
practice because it gets "inside" the student's head and effectively
develops expressive skills (Johnson, 2004). Furthermore, some students
with DS may experience difficulty processing information or
multitasking, due to a lack of sensory or motor development. In this
case, a knowledgeable teacher will try to sit the student in a quiet
space where excess noise, light, and activity will not be distracting.
It has been noted that people with DS have a weakened
immune system and increased susceptibility to infection (Kolata, 1989).
To prevent respiratory infections, for instance, a classroom must be
free of pollutants, allergens, toxins, and chemicals. Although this is a
difficult task to maintain, these factors should be kept to a minimum to
promote growth of the students and to stimulate their overall
development. In addition, if a DS student is taking medication, it is
important for teachers to find out what it is, how it works, and when it
is supposed to be taken, in case the student forgets. Overall, a teacher
who knows about DS will better appreciate the capabilities of their
students, be more supportive and caring towards their classroom needs,
and in turn, influence a student's educational success.