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Biomedical subjects

David S Packard

Publications and source records attributed to David S Packard.

5 recordsLinked to original sources

Congenital vertical talus in four generations of the same family.

OBJECTIVE: This paper presents four generations of a family with radiographically demonstrated congenital vertical talus (CVT) in whom a HOXD10 gene mutation was identified. Some members of the family with this mutation exhibited cavo-varus foot deformity consistent with a Charcot-Marie-Tooth (CMT)-like disorder. DESIGN AND PATIENTS: Physical examination was performed on nearly all of the affected and unaffected family members. DNA was extracted from blood obtained from 14 subjects who showed radiographic and clinical features of CVT (two of whom also had CMT), from two subjects with features of CMT but not CVT, and from 20 related family members who were clinically normal. RESULTS: Radiographs show the appearance of uncorrected CVT in infancy, in childhood, and in adulthood. DNA analysis revealed a mutation in a HOXD10 gene located on chromosome 2 in all of the affected but none of the unaffected family members. CONCLUSION: There is an autosomal-dominant-inherited mutation with complete penetrance which is found in all members of a pedigree with CVT, some of whom exhibit a CMT-like foot disorder. Radiologic findings vary depending on the severity of involvement, treatment provided and age of the patient.

Adolescent↗

A HOX gene mutation in a family with isolated congenital vertical talus and Charcot-Marie-Tooth disease.

Congenital vertical talus (CVT), also known as "rocker-bottom foot" deformity, is a dislocation of the talonavicular joint, with rigid dorsal dislocation of the navicular over the neck of the talus. This condition is usually associated with multiple other congenital deformities and only rarely is an isolated deformity. The reported familial cases are consistent with an autosomal dominant mode of inheritance with incomplete penetrance. In contrast, Charcot-Marie-Tooth disease (CMT) is thought to be a completely distinct heterogeneous group of disorders, with foot abnormalities that typically develop a high-arched "claw foot" appearance later in life. In the present study, DNA was isolated from 36 members of a single upstate (northern) New York white family of Italian descent in which both CVT and CMT were segregating. Whole-genome linkage analysis with Affymetrix GeneChip Mapping 10K Array defined a 7-Mb critical region on chromosome 2q31, which led to candidate-gene sequencing of six HOX genes and detection of a single missense mutation, M319K (956T-->A), in the HOXD10 gene. In the study family, this mutation was fully penetrant and exhibited significant evidence of linkage (LOD 6.33; theta =0), and it very likely accounts for both CVT and CMT in heterozygotes.

Charcot-Marie-Tooth Disease↗

Ischemic necrosis following clubfoot surgery: the purple hallux sign.

Ischemic necrosis, which develops rarely after clubfoot surgery, may have a vascular etiology, since many idiopathic and neurogenic clubfeet have congenital deficiency of the anterior tibial and dorsalis pedis arteries. Dorsalis pedis deficiency is demonstrated more frequently in those clubfeet showing greater deformity. Substantial hypoplasia of the profunda femoris and posterior and anterior tibial arteries was evident in the affected limb of a patient in this series who underwent postoperative arteriography. Herein, we report massive necrosis in seven limbs of six patients after clubfoot surgery and have combined this series with seven previously published cases. Additional cases support our hypothesis that arterial deficiencies put some postoperative clubfeet at risk of perioperative ischemic necrosis. Necrosis occurs in those regions supplied by the congenitally diminished anterior tibial and dorsalis pedis arteries. Knowing that children with congenital vascular deficiency are at risk for ischemic necrosis, surgeons should be alert to the subtle, early signs of ischemia and be prepared to prevent or ameliorate the consequences of this condition. Since hypoperfusion in these postoperative feet is a surgical emergency, we propose clinical guidelines for treatment for this phenomenon, which we have named the purple hallux sign.

Abnormalities, Multiple↗

Pulsed color-flow Doppler analysis of arterial deficiency in idiopathic clubfoot.

This prospective study used pulsed color-flow Doppler sonography to determine differences in the presence and direction of flow through the dorsalis pedis, posterior tibial, and peroneal arteries in a group of children with clubfoot and a comparison group of controls. There was a statistically significant difference in the prevalence of deficient (absent or retrograde flow) dorsalis pedis arteries in children with clubfoot (45%) compared with controls (8%). This indicates that there is an association between some clubfeet and deficiency of the dorsalis pedis artery. There was a trend toward difference in the prevalence of deficiency of the dorsalis pedis artery in the clubfeet that required surgery (54%) compared with those that did not (20%), suggesting that dorsalis pedis artery deficiency may be more prevalent among clubfeet with greater deformity.

Case-Control Studies↗