It's bedlam at the Bishop house in Orem. Andrew, 5, answers the door with a sleepy smile and invites visitors in without waiting for an introduction. He's wearing pajamas with fire engines and Dalmatians on them. Grandma Carolyn, their paternal grandmother, is dishing up cereal for the two youngest kids, who keep up a constant stream of chatter. Their father, Robert, is attending the national Huntington's convention.

They like new people, particularly females. They long for a mother who is home doing mommy things, comforting them when they scrape their knees, tucking them in at night. That has become Robert's job.

If she has seen you a couple of times and you're a woman, Hannah may ask you if you'd like to be her mother. It's not personal. It's just a deep-seated longing. She relates more to the nanny they had for a while than she does to Amy, as far as mothering goes.

Rebecca's in the living room, sketching. She's become quite the artist — and quite the nurturing force to this band of small people. She helps with the kids, showing a maturity and sense of responsibility well beyond her 15 years.

Craig's apt to be messing with the computer. He loves computer games and videos and "guy stuff." And where Craig is, Trevor won't be far away.

Ask Trevor what he likes and he says, proudly, "All the things that Craig likes. I want to grow up to be like my brother. I like to draw the things he draws."

The older children, if asked, will tell you about their mother and grandfather.

"She doesn't talk," Craig says. "We're used to it, so it doesn't seem like such a big deal now."

What they don't talk about is the fear they feel. They are just beginning to understand that they may one day have the same disease that has taken her from them.

The other day, Trevor told his father that he's angry. He misses his mom. And he's convinced that he will probably become sick, too.

When Robert asks them what they're thinking or if they have any questions, they usually say no. Instead, they introduce the topic a little at a time, in digestible spurts, and not very often.

Mostly, they're busy being children.

Rebecca stretches out on the couch to talk. Trevor walks over and sits on her back. "Should I tickle you hard?" she asks, laughing.