Metacarpophalangeal pattern profile analysis: useful diagnostic tool for differentiating between dyschondrosteosis, Turner syndrome, and hypochondroplasia.

PURPOSE: To assess the value of the metacarpophalangeal pattern profile (MCPP) analysis as a diagnostic tool for differentiating between patients with dyschondrosteosis, Turner syndrome, and hypochondroplasia. MATERIAL AND METHODS: Radiographic and clinical data from 135 patients between 1 and 51 years of age were collected and analyzed. The study included 25 patients with hypochondroplasia (HCP), 39 with dyschondrosteosis (LWD), and 71 with Turner syndrome (TS). Hand pattern profiles were calculated and compared with those of 110 normal individuals. Pearson correlation coefficient (r) and multivariate discriminant analysis were used for pattern profile analysis. Pattern variability index, a measure of dysmorphogenesis, was calculated for LWD, TS, HCP, and normal controls. RESULTS: Our results demonstrate that patients with LWD, TS, or HCP have distinct pattern profiles that are significantly different from each other and from those of normal controls. Discriminant analysis yielded correct classification of normal versus abnormal individuals in 84% of cases. Classification of the patients into LWD, TS, and HCP groups was successful in 75%. The correct classification rate was higher (85%) when differentiating two pathological groups at a time. Pattern variability index was not helpful for differential diagnosis of LWD, TS, and HCP. CONCLUSION: Patients with LWD, TS, or HCP have distinct MCPPs and can be successfully differentiated from each other using advanced MCPP analysis. Discriminant analysis is to be preferred over Pearson correlation coefficient because it is a more sensitive and specific technique. MCPP analysis is a helpful tool for differentiating between syndromes with similar clinical and radiological abnormalities.

Metacarpophalangeal pattern profile analysis in Leri-Weill dyschondrosteosis.

PURPOSE: To analyze the metacarpophalangeal profile (MCPP) in individuals with Leri-Weill dyschondrosteosis (LWD) and to assess its value as a possible contributor to early diagnosis. MATERIAL AND METHODS: Hand profiles of 39 individuals with a diagnosis of LWD were calculated and analyzed. Discriminant analysis was applied to differentiate between LWD and normal individuals. RESULTS: There was a distinct pattern profile in LWD. Mean pattern profile showed two bone-shortening gradients, with increasing shortening from distal to proximal and from medial to lateral. Distal phalanx 2 was disproportionately long and second metacarpal was disproportionately short. Discriminant analysis yielded correct classification in 72% of analyzed cases. CONCLUSION: MCPP is not age-related and the analysis can be applied at any age, facilitating early diagnosis of LWD. In view of its availability, low costs, and diagnostic value, MCPP analysis should be considered as a routine method in the patients of short stature where LWD is suspected.

Asn540Lys mutation in fibroblast growth factor receptor 3 and phenotype in hypochondroplasia.

UNLABELLED: Hypochondroplasia is characterized by a disproportionate short stature with rhizomelic shortening of the limbs. Amino acid substitutions Asn540Lys, Asn540Thr and Ile538Val in the fibroblast growth factor receptor 3 (FGFR3) are considered to cause hypochondroplasia. In this study we examined the FGFR3 gene for the previously described hypochondroplasia mutations and the phenotype of 23 probands with clinically and radiologically diagnosed hypochondroplasia. For the phenotype comparison, the patients were divided into two groups: Group 1: hypochondroplasia with Asn540Lys substitution; Group 2: hypochondroplasia with no mutations identified so far. A three-generation family negative for the known hypochondroplasia mutations was examined with polymorphic markers flanking the FGFR1, FGFR2 and FGFR3 genes. Nine (39%) of 23 probands were found to be heterozygous for the Asn540Lys substitution. The individuals positive for the Asn540Lys substitution were significantly more disproportionate than the individuals without this mutation. In this respect, a genotype-phenotype correlation was found in our patients. However, some individuals belonging to the group without mutations identified so far showed similarly abnormal proportions. Genotyping/haplotyping in the three-generation family with hypochondroplasia showed that FGFR1, FGFR2 and FGFR3 genes were not linked to the hypochondroplasia phenotype in this family, thus further confirming the genetic heterogeneity of hypochondroplasia. CONCLUSION: Individuals with hypochondroplasia heterozygous for the Asn540Lys substitution are significantly more disproportionate than individuals without this mutation. Our study further confirms the clinical and genetic heterogeneity of hypochondroplasia.

Swedish metacarpophalangeal standards compared with previously published norms.

PURPOSE: Metacarpophalangeal lengths are used to create pattern profiles that are useful for assessment of skeletal dysplasias and malformation syndromes. The purpose of this study was to establish Swedish standards and compare them with previously published norms. MATERIAL AND METHODS: A group of healthy Swedish children was followed longitudinally from the age of 1 month to 18 years. The length of the tubular bones of the hand was measured on radiographs. In addition to the conventional measurements including epiphyses, diaphyseal lengths alone were recorded. RESULTS: Means and standard deviations of the metacarpophalangeal lengths are presented by gender and age. CONCLUSION: In spite of reasonably good correlation to previously published norms, demonstrated deviations encourage us to recommend the use of local standards whenever available.