And in the past it was customary to leave these conditions untreated as these children were not considered "worthy" of treatment. Often the medical community did not think their "quality of life" was sufficient to warrant treatment for most medical treatments, particularly surgery.
Newborn: (0-1 month)
Congenital heart disease (CHD) occurs in 40-60% of Down's syndrome newborns...Cardiac defects are responsible for a significant degree of morbidity and mortality during the first two years of life. GI tract anomalies are seen in 6-12% of Down's syndrome newborns,...Physiologic complications such as oral motor dysfunction or gastroesophageal reflux are also seen...There is also an increased incidence of congenital hypothyroidism due to absence or aplasia of the thyroid gland which occurs in about 1 to 2% of newborns.Infancy: (1-12 months)
Transient myeloproliferative disorder (TMD) is sometimes seen in the first few months of life....Newborns with TMD are at increased risk for developing acute non-lymphocytic leukemia (ANLL) before the age of 5 years. Infants with Down's syndrome are susceptible to both viral and bacterial infections of the respiratory tract. Recurrent otitis media, sinusitis, and rhinitis are frequent problems as are bronchiolitis and pneumonia. Lower respiratory tract infections may be a significant cause of morbidity during infancy particularly in those with uncorrected cardiac disease. Childhood: (1-12 years)
Disorders of thyroid function are particularly common in children with Down's syndrome...Obstructive sleep apnea (OSA) is noted in > 30% of children with Down's syndrome. ..Down's syndrome is associated with approximately 2% of all cases of acute leukemia in children...Within the ANLL group, there is a remarkable increase in the incidence of acute megakaryocytic leukemia in those children with a history of TMD...Children with Down's syndrome are susceptible to subluxation of the hips, patella, and C-spine. Up to 15% of children show x-ray evidence of asymptomatic C-1/C-2 instability,...http://www.intellectualdisability.info/lifestages/ds_child.htmSo essentially, these children were allowed to die through neglect. Now they are much more likely to get treament similar to that of the "normal" population thanks to advocacy of their parents, other family members, staff and other community members. This has contributed greatly to their life expectancy and quality of life.