These deficits become more apparent over time and include developmental delays, social problems, and retardation.

Symptoms include brittle hair, mild mental retardation and nail dysplasia.

Neurological signs include poor muscle control and moderate mental retardation.

Several X-linked syndromes include retardation as part of the presentation.

As used by most medical researchers and practitioners, the term does not include mental retardation, which means the failure to develop normal intelligence.

Long term disabilities include poor growth, mental retardation, and ovarian failure in females.

Clinical symptoms include excitability, weight loss, and severe retardation of growth and hair development.

They also include severe mental retardation and serious heart defects that can be lethal.

Other symptoms can include respiratory difficulties, mental retardation, and certain physical characteristics.

The disease is fatal, with symptoms that include neurological damage and severe mental retardation.