Table 2.

Clinical characteristics of patients.

	Patient 1	Patient 2
Sex	Female	Female
Race/ethnicity	White	Hispanic
Age at initial presentation	<6 months	<12 months
Features at initial presentation	Chronic diarrhea, poor growth	Chronic diarrhea, vomiting, poor growth
Endoscopic features	Atrophic small bowel mucosa, with shortened or absent villi and scalloping of folds	Stomach with diffuse inflammation, characterized by friability, erythema, and mucus plaques. Duodenum with diffuse villous atrophy and scalloping.
Histologic features	Duodenal mucosa with total villous atrophy, crypt hyperplasia, and patchy intraepithelial lymphocytosis	Duodenal mucosa with villous blunting, increased intraepithelial lymphocytes and lamina propria expansion by a mixed inflammatory infiltrate. Stomach with moderate to severe chronic active gastritis.
Age at diagnosis of CTLA4 haploinsufficiency	18.8 years	14.0 years
CTLA4 mutation	c.457+2T>C	De novo heterozygous variant in CTLA4 in exon 1, c71_72del (p.Leu24Profs*35)
Medical history	- Celiac-like disease - Hashimoto’s thyroiditis - Addison’s disease - Cytopenias - Drug-induced lupus (adalimumab) - Mild scalp psoriasis - Lichen sclerosis	- Celiac-like disease - Pulmonary coccidiomycosis - Erythema nodosum - Avoidant restrictive food intake disorder - Depression
Family history	- Father with CTLA4 haploinsufficiency and melanoma. - Paternal first cousin with type 1 diabetes mellitus.	- Maternal grandmother with type 1 diabetes mellitus
Consanguinity	None	None
Treatments	- GFD (NR) - Budesonide (NR) - 6-mercaptopurine (cytopenias) - Methotrexate (NR) - Adalimumab (drug-induced lupus) - Prednisone (LOR) - Abatacept (remission) - IVIg	- GFD (NR) - Budesonide (NR) - Abatacept (remission) - IVIg
Outcome	Clinical and endoscopic remission on abatacept	Clinical and endoscopic remission on abatacept
Follow-up period, since diagnosis of CTLA4 haploinsufficiency	5.0 years	2.0 years

NR, non-response; LOR, loss of response; n/a, not available.