Down Syndrome Overview

Down Syndrome

Introduction

Down syndrome is a genetic disorder characterized by intellectual disability and physical abnormalities due to the presence of an extra chromosome 21, resulting in three copies where two would normally exist. This condition, also known as trisomy 21, affects approximately 1 in every 800 live births worldwide. It is the most common genetic disorder causing intellectual disability.

Cause

Down syndrome occurs when an individual inherits an extra copy of chromosome 21. Most cases result from a random event called nondisjunction, during which chromosome 21 fails to separate properly after cell division, resulting in two daughter cells with an extra chromosome 21. Around 95% of Down syndrome cases are caused by nondisjunction.

Symptoms

Symptoms vary widely among individuals with Down syndrome, reflecting differences in the triplication of various chromosome 21 genes. However, typical features include:

• Intellectual disability: Individuals with Down syndrome generally experience varying degrees of cognitive difficulties.
• Physical characteristics: These may include facial features such as a flattened facies and upward-slanted eyes, as well as low muscle tone, loose joints, and short fingers.

Additional Conditions

People with Down syndrome are prone to numerous additional medical issues. Some notable associations are:

• Alzheimer's disease: Early onset Alzheimer's disease is significantly more common in people with Down syndrome.
• Cardiac defects: Approximately half of individuals with Down syndrome have congenital heart defects.
• Increased susceptibility to infection: People with Down syndrome tend to have less robust immune responses, making them more vulnerable to infections.

Diagnosis

Typically, Down syndrome is diagnosed before birth using ultrasound imaging techniques, such as nuchal translucency measurements, or after birth through blood tests. It is essential to diagnose Down syndrome accurately, as early intervention can improve outcomes and supportive care.

Management and Support

Management of Down syndrome primarily focuses on addressing specific symptoms and medical needs in collaboration with healthcare professionals, educators, and family members. Services may include medical care, therapies, family support, and special education programs tailored to meet the unique requirements of individuals with Down syndrome.