Narrative Pedigree 

Type

Data Visualization

Creates

Nothing. It draws the family built in an earlier Family Pedigree stage

Uses prompts

No

Configure in

• Architect ClassicArchitect Classic (not available)
• Architect

Run in

• Interviewer ClassicInterviewer Classic (not available)
• Interviewer
• Fresco

Requires protocol schema 8 or later.

The Narrative Pedigree is a companion to the Family Pedigree. It draws the family a participant built in an earlier Family Pedigree stage and shows how one or more conditions recorded in that family may be inherited. The participant chooses a condition, and each person's symbol shows their status for it in standard pedigree notation (Bennett et al., 2008, 2022). The participant can then focus on any person to see the relatives through whom the condition could have reached them.

The interface is read-only. It never adds, changes or removes people, relationships or attributes, and it records nothing in the interview data. Every status it shows is worked out afresh from the family as the source stage recorded it.

The interface is most useful in formal pedigree research and genetic counseling, where a condition's inheritance pattern is known and the family records biological relatedness. In research on families as participants define them, where biological ties may be incomplete or deliberately left out, its inferences rest on whatever biological structure the participant chose to record, and should be read with that in mind.

Configuring the stage

The stage editor in Architect has four sections of its own, followed by the Skip logic and Interviewer guidance sections that every stage has.

Pedigree source

Choose the Family Pedigree stage whose family this stage draws in Source stage. Only Family Pedigree stages that come before this one are offered, and Architect explains when there are none. If the chosen stage is later deleted, moved after this one, or changed to another interface, Architect reports it and the stage cannot be saved until another source is chosen.

Every condition maps an attribute of the source stage's person type, so choosing a different source removes every condition, after a confirmation. While a Narrative Pedigree reads a Family Pedigree, that Family Pedigree's person type cannot be changed. Point the Narrative Pedigree at another source, or remove it, first.

The stage draws the participant and everyone connected to them through the source stage's relationships: partners (current or not), parents of every kind, children, and their relatives in turn. Someone of the same person type who is not connected to the participant through those relationships is left out, even if another stage added them or tied them to the participant with a different kind of connection.

Disease mappings

Each condition the participant can choose is a row in Disease mappings. Create new disease opens a dialog with four fields, all required:

• Disease label: the condition's name, shown in the participant's condition menu. Each condition needs a different name, in every language of the protocol.
• Color: one of the eight node colors. The condition's statuses, and its symbols in the key, are drawn in it.
• Node attribute: the boolean attribute that records who is affected. Only attributes recorded by one of the source stage's nomination prompts are offered, and each can be mapped by only one condition. If none is offered, add a nomination prompt to the Family Pedigree that asks who has the condition.
• Inheritance pattern: how the condition is passed from parent to child. Every inference the interface makes depends on it (see How statuses are inferred).

The eight inheritance patterns are autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, Y-linked, mitochondrial, multifactorial and unknown. For Multifactorial and Unknown, the interface shows only who was recorded as affected and infers no other status.

The stage needs at least one condition. The order of the rows is the order of the participant's condition menu.

At-risk statuses

Show possible (at-risk) statuses is off by default. While it is off, the pedigree shows only statuses that are recorded or follow with certainty from the family's structure. When it is on, the pedigree also shows the two statuses that are only possible, may develop and may carry, and the key lists them. See Possible statuses before turning it on.

Customize built-in wording

The Customize built-in wording section holds the words participants read on the stage. Each starts as Network Canvas words it, in every language it has wording for, and you can change and translate it like any other text. Your protocol keeps only the wording you change (see Words Network Canvas supplies).

Under Specific to this stage are:

• the condition menu's text while no condition is chosen, which is also its choice for showing none ("Select a condition");
• the label of the Save snapshot button;
• the titles of saved snapshots, one for a snapshot of a condition and one for a snapshot focused on a person. They show the stage's label and the condition's name, and the second also shows the person's name, where their placeholders are.

Under Shared by every stage of this kind is the wording every Narrative Pedigree stage shows alike: the heading of the key, the meaning of each symbol in it ("Has this condition", "Will develop this condition", "Carries this condition", "May develop this condition", "May carry this condition" and "Not known"), and the tooltip of the Clear focus button. Each meaning can instead name the condition being shown, inserted as a pill with the field's piped text button. The two possible statuses are there only while a Narrative Pedigree stage has Show possible (at-risk) statuses switched on. Beside them are the descriptions of the zoom buttons and the name and description of the Show the whole family button, which every Narrative Pedigree and Family Pedigree stage shows alike. A change to any of these applies to all those stages, and is saved as soon as you leave the field.

What the participant sees

The stage opens on the whole family, drawn as the Family Pedigree draws it and fitted to the screen. Each person is labeled as they were on the Family Pedigree. The participant is labeled "You", and everyone else by their name. A relative the participant did not name is labeled by how they are related to the participant, in the words the Family Pedigree used ("Mother" or "Egg parent", for example). If your study encrypts the name attribute, the participant is asked for their passphrase, and relatives are labeled by how they are related until it is entered. A person recorded as adopted is drawn between brackets.

Each symbol takes the shape the Family Pedigree's Symbols choice gives it. Mapped to sex assigned at birth, a person recorded female is drawn as a circle, a person recorded male as a square, and everyone else as a diamond.

A toolbar below the family holds, in reading order (from right to left in an interview shown in a right-to-left language):

• the condition menu, which lists every condition beside its color, after a first choice that shows none;
• Clear focus, while a person is focused on;
• Zoom out, Zoom in, and a button that shows the whole family;
• Save snapshot.

The participant can also drag the canvas to pan it, and zoom with the mouse wheel, by pinching, or with the + and − keys.

Until a condition is chosen, every person is drawn as a plain symbol in the person type's color, with their label inside it. Choosing a condition redraws each symbol in standard notation, in the condition's color, with the label beneath it, and opens a key beside the family that explains each symbol. The participant can widen or narrow the key by dragging its edge. Only one condition is shown at a time. Choosing Select a condition from the menu returns to the plain drawing and closes the key.

The symbols

The key draws each of its symbols as a circle; on the pedigree, each person keeps their own shape. Where more than one rule gives a person a status, the more certain status is shown: a recorded status before an inferred one, and an inferred certain status before a possible one. Between the two possible statuses, may develop is shown before may carry.

Focusing on one person

Once a condition is chosen, selecting a person focuses on them. An arrow above their symbol marks them, and the pedigree highlights the relatives through whom the condition could have reached them and the lines of descent it passed along. Everyone and every line not on that path are dimmed. Clear focus, the Escape key, or a click on an empty part of the canvas clears the focus. Changing to another condition keeps the focus, and returning to Select a condition clears it.

The path follows the inheritance pattern of the condition:

• Autosomal (dominant or recessive), multifactorial and unknown: through either parent.
• X-linked: a male's X chromosome comes from his mother, so his path runs only through her. For an X-linked recessive condition, a female who carries it and whose father is affected received it from him, so her path runs only through her father, unless she is herself affected or her mother is affected.
• Y-linked: from father to son.
• Mitochondrial: through the parent who gave the egg.

The path passes only through relatives who have a status for the condition, and the person focused on is highlighted alone when none of their parents has one. It is traced from every status the interface infers, including possible statuses while they are hidden, so with Show possible (at-risk) statuses off, a relative shown as Not known can still be on the path.

Keyboard and screen readers

The family is a single stop in the tab order. The arrow keys move between people by where they sit in the tree, and Enter or Space focuses on the person who has keyboard focus. People cannot be focused on until a condition is chosen, but they can still be reached with the arrow keys.

Screen readers read each person's status for the chosen condition with their name, and announce each change of condition or focus. The symbols themselves are not read out, so a person's status is never announced unless it is drawn.

Saving a snapshot

Save snapshot saves a PNG image of the whole family on a white background, at its natural size whatever part of it is on screen. The image is drawn as the pedigree is for the chosen condition and focus, with the key once a condition is chosen. It is titled with the stage's label, and, once a condition is chosen, with the condition and the person focused on, using the snapshot titles in Customize built-in wording. The file is saved to the participant's device and is not part of the interview data.

How statuses are inferred

The interface works out each person's status from three things: who was recorded as affected, the family's biological structure, and each person's sex assigned at birth. Inference is conservative. A status is shown only where the recorded family supports it, and a person is shown as Not known whenever the family does not say more.

The model gives no probabilities, and it does not represent variable penetrance (beyond the cases described below), phenocopies, mosaicism or uncertain variants. Its statuses indicate where in the family to look, and are no substitute for clinical assessment.

Which relationships pass a condition on

Only biological parents and donors pass a condition on. Adoptive, social and step parents, surrogates, and partners never do, so no status is ever inferred across them.

Sex assigned at birth

X-linked and Y-linked inheritance depend on sex assigned at birth, and gender identity plays no part in them. A person recorded as female or male is treated as recorded. A person recorded as intersex is always treated as of uncertain sex, because neither one X chromosome nor two can be assumed. A person whose sex is not known, who preferred not to say, or who was not asked is placed by the gamete they gave a child, the egg or the sperm, when the Family Pedigree's gamete rule works it out from the child's other parent, and is otherwise treated as of uncertain sex. X-linked and Y-linked inheritance through a person of uncertain sex is left unresolved rather than guessed. Mitochondrial inheritance follows the egg rather than sex, so it passes through anyone the gamete rule shows gave an egg, including a person recorded as intersex.

Inferences under each pattern

In the following list, female and male refer to sex assigned at birth as described above.

• Autosomal dominant. The descendants of an affected person may develop the condition. An unaffected person between an affected ancestor and an affected descendant carries it, when the descendant's condition can only have come through them; this is the non-penetrant carrier of a dominant condition. The parents of an affected person with no affected ancestor are never marked as carriers, because the condition may have arisen anew.
• Autosomal recessive. Both genetic parents of an affected person, and every child of an affected person, carry the condition. A person whose genetic parents are both affected will develop it. A person whose genetic parents both carry it may develop it; one with a single carrier parent recorded may carry it. The parents and siblings of an affected person's carrier parents may carry it.
• X-linked recessive. Every daughter of an affected male carries the condition, and his sons inherit nothing from him. A female with two affected sons, or with an affected son and an affected brother who shares her mother, carries it. The mother of a single affected male otherwise may carry it, as may his maternal grandmother and maternal aunts, and his maternal uncles may develop it. From each female who carries or may carry the condition, daughters may carry it and sons may develop it. Relatives connected only through an unaffected male, such as a mother's half-sibling who shares only her father, are not marked.
• X-linked dominant. Every daughter of an affected male will develop the condition, and his sons inherit nothing from him. Every child of an affected female may develop it, and the inference continues down through each such child by the same rules.
• Y-linked. Every male in the unbroken male line of an affected male, including his father, sons, brothers, paternal uncles and their sons, will develop the condition. Nothing passes to or through a female.
• Mitochondrial. The condition follows the egg. Every child of an affected female may develop it, and it continues down through daughters only. The affected person's maternal line (their mother, her mother, and so on) and that line's other children may develop it too. Where a child was conceived with a donor egg, the line follows the donor, not the person who carried the pregnancy. Because the expression of mitochondrial conditions varies, inferred relatives are never marked as certain to develop them.
• Multifactorial and unknown. Only the people recorded as affected are marked.

The Family Pedigree allows a child at most one genetic parent recorded female at birth, so mitochondrial donation, in which one egg gives the nucleus and another the mitochondria, cannot be represented.

Possible statuses

The two possible statuses, may develop and may carry, are inferred rather than observed. They are a strong visual signal that can be read as established fact. Standard pedigree nomenclature deliberately encodes no probability in a symbol, and the interface draws these statuses as the corresponding certain symbol with a question mark added, never with a fill. They are intended for clinician-directed use, where a professional interprets them in context.

Best practices

Try to avoid

References

Bennett, R. L., French, K. S., Resta, R. G., & Doyle, D. L. (2008). Standardized human pedigree nomenclature: Update and assessment of the recommendations of the National Society of Genetic Counselors. Journal of Genetic Counseling, 17(5), 424–433. https://doi.org/10.1007/s10897-008-9169-9

Bennett, R. L., French, K. S., Resta, R. G., & Austin, J. (2022). Practice resource-focused revision: Standardized pedigree nomenclature update centered on sex and gender inclusivity. Journal of Genetic Counseling, 31(6), 1238–1248. https://doi.org/10.1002/jgc4.1621