Which condition is best associated with low muscle tone and development issues in infants?

The condition most closely associated with low muscle tone and developmental issues in infants is Down syndrome.

Down syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of an extra chromosome 21. One of the hallmark characteristics of this condition is hypotonia, or low muscle tone, which is often noticed at birth. Infants with Down syndrome frequently demonstrate delayed development in motor skills due to this muscle weakness.

In addition to hypotonia, infants with Down syndrome may also exhibit a range of developmental delays that can affect language, cognitive abilities, and physical development, further emphasizing the significance of low muscle tone in their overall development.

Prader-Willi Syndrome and DiGeorge Syndrome can also feature low muscle tone and developmental issues, but they are not as prominently associated with hypotonia and early developmental challenges as Down syndrome. Tay-Sachs Disease, while it does lead to developmental challenges, is primarily associated with neurodegeneration rather than low muscle tone as an early identifying feature.