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Large Number of Adolescent Males with Fabry Disease Undergo Sudden, Pronounced Height Increase
February 18, 2017—San Diego, California—Over 35% of males in a cohort of patients with Fabry disease underwent a clinically substantial increase in height over their projected growth curve during adolescence/young adulthood.
This finding of a study of a retrospective registry review was presented at the 13th Annual WORLDSymposium, from February 13–18.
Dawn Jacob Laney, MS, of Emory University, Atlanta, Georgia, explained that Fabry disease is an X-linked progressive, multisystemic inborn error of glycosphingolipid catabolism resulting from mutations in the α-galactosidase A gene.
The incidence of Fabry disease is estimated to be between one in 40,000 and one in 120,000 live births. Symptoms are typically first experienced in early childhood and can be very difficult to understand. In fact, the rarity of Fabry disease to many clinicians sometimes leads to misdiagnoses. Manifestations of the disease usually increase in number and severity as the affected individual ages.
Life expectancy of males with Fabry disease was 58.2 years in registry data covering the period 2001–2008. The most common cause of death was cardiovascular disease, and most of those had received kidney replacements. The condition affects hemizygous males (that is, all males), as well as homozygous, and in many cases, heterozygous females. While males typically experience severe symptoms, women can range from being asymptomatic to suffering severe symptoms.
Slow growth (mean height/weight <50th percentile) in paediatric males affected with Fabry disease is a documented feature of the condition.
Ms. Laney hypothesised that during adolescence/young adulthood, these shorter-stature males with Fabry disease may experience a sudden increase in growth and move into higher percentiles.
“We are fortunate,” Ms. Laney said, “that at the Emory Lysosomal Storage Disease Center we can work with patients and families living with Fabry disease across all ages and over the course of their lives. Our preteen patients often ask about their final adult height. Clinically, it seemed that some of the young men were experiencing a delayed, fast growth spurt that ended in their achieving a higher final adult height than expected from observing their earlier growth.”
“I was curious to learn,” she added, “whether this growth was merely related to our small sample size or a pattern seen at other centres as well. Since we participate in the Fabry registry (Sanofi-Genzyme) we were able to submit a data request and obtain a larger patient sample size.”
Height values from198 males affected with Fabry disease enrolled in the Fabry Registry were analysed regardless of enzyme replacement therapy status. These males were age 12–21 years, had initial height values in the <50th percentile, and at least one follow-up height value 2 or more years later when <30 years of age.
All were then categorised into two groups: stable (<50% for height) and growth (moved into the ≥50% for height). An additional subset of the growth group of males moving into the ≥75% was also created. Mean age at baseline height values was similar for both groups: age 15.5 years for stable males and age 14.6 years for the growth group. Of the 198 males, 128 (65%) stayed in the stable group.
Seventy males (35%) moved into the growth group. Twenty of the 70 males in the growth group reached the 75th percentile. Over 35% of males in this cohort of patients with Fabry disease underwent a clinically substantial increase in height over their projected growth curve during adolescence/young adulthood.
Ms. Laney concluded that further research should be undertaken in the male growth group to determine whether this growth spurt could be correlated with a change in expected course of Fabry disease. Possible factors to explore are positive health changes such as gastrointestinal improvements, improved nutrition, or years of disease-specific therapy for Fabry disease.
“We are very interested in learning more,” Ms. Laney said, “about the subset of young men with Fabry disease who experienced rapid growth in height. We hope to uncover factors correlated with this growth via future research. In fact, our first protocol to explore this topic further was just approved by our Institutional Review Board and we are recruiting for the study now.”