medwireNews: The parental heights of girls with Turner syndrome are infrequently measured, despite their importance in diagnosis and setting growth targets, say researchers.

Among 172 girls diagnosed with Turner syndrome at a single clinic, only 94 had measured heights for both parents. The 92 of these with records of their own heights had an average height standard deviation score (SDS) of –2.63, whereas the average SDS for the lower end of their parental target range (LTR) was –1.77, giving a difference of 0.86.

The difference was 0.56 for 31 patients with only one measured parental height, and Malcolm Donaldson (Glasgow University School of Medicine, UK) and co-researchers speculate that, because mothers more often attend clinics with their daughters, the fathers mostly reported – and overestimated – their heights, inflating the difference between height SDS and LTR.

The 15 patients for whom both parental heights were reported had a difference of 0.92, which the researchers interpret as mothers underestimating and fathers overestimating their heights, “so that the errors cancel one another out”.

“Clearly, it is not desirable to subject girls with a growth disorder such as Turner’s syndrome to the vagaries of reported height”, they write in the European Journal of Pediatrics.

Among the 92 girls with measured parental heights, individual height SDSs were below the LTR in 85% of cases; in other words, height had 85% sensitivity for Turner syndrome diagnosis. In the whole cohort, 82% of the girls had a height SDS below –2.0, so around one in five patients would be missed if diagnosis were based primarily on height.

“We should stress that in our study population, short stature was by no means the key factor in the diagnosis of Turner syndrome in every patient”, say the researchers. “On the contrary, the diagnosis had been made before 1 year in 40% of the girls, and would have been related to features such as dysmorphism, lymphoedema and to problems such as aortic coarctation rather than short stature.”

But they emphasise that height measurement of both the patients and their parents not only assists diagnosis in less obvious cases, but also determines an accurate target height for Turner syndrome patients that “the family can realistically expect and which the clinician should aim to achieve”.

Yet just 54.6% of girls had measured heights for both parents, despite the setting of a specialist Turner syndrome clinic, and the team suggests that “this is likely to be the case in other centres”.

They conclude: “A more rigorous approach is required to ensure that both parents are measured in clinic and that missing heights from the initial visit are secured at a later stage where possible.”

By Eleanor McDermid

Eur J Pediatr 2017; Advance online publication

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