Background: Hypochondroplasia is an osteochondrodysplasia inherited in an autosomal dominant pattern that results in a disproportionately short stature, characteristic facial features and skeletal alterations such as lordosis and genu valgum. Haploinsufficiency of the fibroblast growth factor receptor 3 gene (FGFR3) is responsible for 5070% of the cases, but a negative result doesnt rule it out.
Case presentation: We report an 11 years and 10 months old boy with family history of disproportionately short stature and personal background of small for gestational age (39 weeks, birth weight 2020 g (−3.2 S.D.), length 44.5 cm (−3.2 S.D.). He begins puberty at the age of 10. Physical examination: weight: 37.6 kg (−0.53 S.D.), height 133.5 cm (−2.1 S.D.), sitting height-to-standing height ratio (SH/S) 0.57 (>97), and Tanner IV (2020 cc). Clinical features suggestive of hypochondroplasia with facial dysmorphia with frontal bossing, large hands with enlargement of interphalangeal joints, short and wide fingers, limited forearm supination and short limbs with rhizomelia, and significant muscle hypertrophy. Complementary examination: skeletal survey: rhizomelia, Madelungs deformity, and widened lumbar interpeduncular distance. Bone age: 14 years. Molecular genetic analysis of FGFR3: negative. HCG-ARRAY: 0.045 Mb deletion of the regulation region of the gene SHOX, found as well in the mother and the siblings.
Conclusion: In patients with clinical features suggestive of hypochondroplasia and negative result in molecular genetic analysis of FGFR3, defects in the gene SHOX should be ruled out.
01 Oct 2015 - 03 Oct 2015