Down Syndrome

About Down Syndrome

Basic information

What is it?

Down syndrome is a genetic condition that usually causes mild to moderate intellectual disability, shorter stature, and characteristic facial features that make it recognizable.

It occurs due to an extra chromosome — specifically, an extra copy of chromosome 21. Chromosomes are packets that contain the body’s genetic material.

Humans have 23 pairs of chromosomes in each cell, for a total of 46. Chromosomes come in pairs because we inherit half (23) from our mother and half (23) from our father. Each pair carries the same type of information, but in different versions. For example, a pair of chromosomes contains instructions for eye color: the maternal chromosome might code for blue eyes, the paternal for brown.

Cause

Sex cells (eggs in women and sperm in men) differ from other body cells because they contain only half of the genetic material: 23 chromosomes instead of 23 pairs. When an egg and sperm combine, they form a cell (zygote) with 23 pairs of chromosomes, completing the genetic material for a human.

Down syndrome most often results from an error in the formation of sex cells. Instead of 23 chromosomes, the egg or sperm contains an extra copy of chromosome 21. When this cell combines with a normal sex cell, the resulting zygote has 47 chromosomes instead of 46.

How does it manifest?

Down syndrome is also called trisomy 21, as there are three copies of chromosome 21 instead of the usual two.

The extra genetic material disrupts normal cell function and causes multiple effects.

People with Down syndrome are often recognizable by physical features:

  • Distinctive eye shape and wider spacing

  • Flatter nasal bridge

  • Relatively larger tongue (often slightly protruding in infants)

  • Different finger and toe arrangements (e.g., larger gap between the big toe and other toes, shorter and wider fingers)

  • A single transverse palmar crease

However, many consequences are less visible: delayed development (shorter stature, intellectual delay), low muscle tone, joint instability, hearing and vision issues, congenital heart defects, thyroid problems, digestive issues, and reduced fertility.

What about other trisomies?

Only three other trisomies are viable:

  • Trisomy 18: Edwards syndrome

  • Trisomy 13: Patau syndrome

  • Sex chromosome trisomies: extra X or Y chromosome

Why only four trisomies? Most chromosomes carry critical instructions for vital organs. Extra copies of these chromosomes usually prevent a zygote from developing, resulting in miscarriage. Only trisomies of chromosomes 21, 18, 13, and sex chromosomes are sometimes compatible with life. Even so, trisomy 18 and 13 are severe, and most affected children die within weeks or a few years.

Photo zavod uvid 13.09.2025_17
Photo zavod uvid 13.09.2025_13

Filip Kocman

– exceptionally skilled at the game Ludo (Človek, ne jezi se)

Although Filip was actually born on the twenty-first, his official birth date is recorded as the twenty-second. Shortly after birth he needed resuscitation, and doctors managed to revive him only twenty minutes past midnight.

If you saw him today — confidently standing on a paddleboard, playing bocce, or battling through a game of Ludo — you’d hardly imagine the fierce fight for life he endured in his first days. He was born with a severe heart defect. For a month and a half he lay in an incubator instead of in his mother’s arms, receiving oxygen. His parents weren’t allowed to touch him — but Filip’s mother, Polonca, couldn’t bear that. With the help of one of the nurses, she stroked him in secret. After a few days, doctors gave Filip his diagnosis: Down syndrome.

Instead of heading to university or work, Filip attends a vocational and occupational centre. He usually returns home around noon, and then he and Polonca take care of household tasks together. He unloads the dishwasher, makes the bed, sweeps the floor, hangs the laundry. When his father gets home from work, they go for an afternoon walk; they average around ten thousand steps a day. When the weather is warm, they often go cycling — his parents, Filip, and his younger sister, Nina.

Filip also trained in swimming, belongs to a bocce club, and plays table tennis in the basement at home. But more than sports, he loves board games. Those are his favourite — and when it’s time for board games, the whole family gathers.

Want to learn more?

Brochure on Down syndrome

Do you want to better understand Down syndrome?

Watch the video.
Agnes Kojc

#RealTalk

“Moja mama je bila vzgojiteljica, pa sem Filipa želela dati v redni vrtec, čeprav so me vsi gledali: “Kako bo šel v redni vrtec,” da je “drugačen”.

Tudi na igrišču te pogosto gledajo postrani, nihče se mu ne upa približati.

Najbolj smo to videli v vrtcu, med otroci, ko so bili nastopi, da se nekateri starši odzovejo negativno, gledajo ga postrani … in avtomatsko otrok posnema starša in avtomatsko je situacija taka, da ga takoj želijo izločiti, takoj s prstom nanj kažejo.

Seveda mi tega nismo dovolili in smo vztrajali dalje, tako da je cel vrtec naredil v normalnem vrtcu.”

Polonca Kocman

Polonca Kocman

“Včasih sem se spraševala, zakaj se je to zgodilo nam.

Danes pa bom rekla, da je to za nas en blagoslov. Dejansko nas Filip vse povezuje.

Več smo skupaj, več komuniciramo, ob večerih igramo Človek ne jezi se, dela si delimo.

Dejansko smo 24 ur nekako povezani.

On nas povezuje in nam daje tisto, česar mogoče drugače ne bi imeli.”

Polonca Kocman

Polonca Kocman

#INSPIRE

The INSPIRE project is carried out under the Erasmus+ programme.

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or CMEPIUS. Neither the European Union nor the granting authority can be held responsible for them.