Holoprosencephaly and split hand/foot: an additional case with this rare association

Novel heterozygous mutation in the extracellular domain of FGFR1 associated with Hartsfield syndrome

Heterozygous kinase domain mutations or homozygous extracellular domain mutations in FGFR1 have been reported to cause Hartsfield syndrome (HS), which is characterized by the triad of holoprosencephaly, ectrodactyly and cleft lip/palate. To date, more than 200 mutations in FGFR1 have been described; however, only 10 HS-associated mutations have been reported thus far. We describe a case of typical HS with hypogonadotropic hypogonadism (HH) harboring a novel heterozygous mutation, p.His253Pro, in the extracellular domain of FGFR1. This is the first report of an HS-associated heterozygous mutation located in the extracellular domain of FGFR1, thus expanding our understanding of the phenotypic features and further developmental course associated with FGFR1 mutations.

Novel de novo heterozygous FGFR1 mutation in two siblings with Hartsfield syndrome: a case of gonadal mosaicism

Hartsfield syndrome has been recently reported to be associated with mutations in FGFR1 however, to this date; no familial cases have been reported. In this report, we describe two siblings with Hartsfield syndrome and a novel de novo FGFR1 mutation suggesting gonadal mosaicism. The proband presented at our institution at age 6 years with a clinical diagnosis of Hartsfield syndrome and requesting further genetic evaluation. Previous studies included a normal karyotype, oligonucleotide array, and single gene testing for nonsyndromic holoprosencephaly (SHH, SIX3, ZIC2, TGIF). At the age of 6 years, exome sequencing was performed and a de novo novel missense variant was identified in FGFR1 (coding for fibroblast growth factor-1) on chromosome 8p12: c.1880G>C (p.R627T). Subsequently, a younger sibling was born with the same phenotype (holoprosencephaly, ectrodactyly of bilateral hands and feet and bilateral cleft lip and palate). Targeted sequencing of FGFR1 revealed the identical variant that was previously identified in the proband. To our knowledge this observation is the first documentation of familial recurrence of Hartsfield syndrome. As both parents were negative for the sequence variant in FGFR1 gene by testing peripheral blood samples, this suggests gonadal mosaicism. The frequency of gonadal mosaicism in Hartsfield syndrome is not known however given our case, this possibility should be taken in to consideration for recurrence risk estimation in children of clinically unaffected parents.

Microduplication of Xq24 and Hartsfield syndrome with holoprosencephaly, ectrodactyly, and clefting

The combination of holoprosencephaly and ectrodactyly, also known as Hartsfield syndrome, represents a unique genetic entity. An X-linked recessive mode of transmission has been suggested for this condition based on the observation that male patients have preferentially been affected. Thus far, no candidate genes have been suggested on the X chromosome. We report a male patient with a full-blown Hartsfield syndrome phenotype who had microduplication at Xq24 involving four genes. He presented with bilateral ectrodactyly of the hands (both hands had four fingers with a deep gap between the 2nd and 3rd digits), cleft lip and palate, and a depressed nasal bridge. Magnetic resonance imaging of the brain revealed lobar holoprosencephaly. His G-banded karyotype was normal. Array comparative genomic hybridization (CGH) using the Agilent 244K Whole Human Genome CGH array revealed a microduplication at Xq24 of 210 kb. Parental testing revealed that the deletion was derived from the asymptomatic mother. Of the genes on the duplicated interval, the duplications of SLC25A43 and SLC25A5 appeared to be the most likely to explain the patient's phenotype. From a clinical standpoint, it is important to point out that the propositus, who performs relatively well with holoprosencephaly and has a developmental quotient around 70, has survived multiple life-threatening episodes of hypernatremia. Awareness of the risk of hypernatremia is of great importance for the anticipatory management of patients with ectrodactyly and an oral cleft, even in the absence of overt hypotelorism.

Holoprosencephaly and ectrodactyly: Report of three new patients and review of the literature

Holoprosencephaly (HPE) and ectrodactyly represent congenital malformations of the developing forebrain and developing digits, respectively. The combination of these conditions is rare, with only 15 cases known to date (12 previously reported, and 3 new cases described here). While the findings in these patients overlap with previously described genetic conditions, the similarity in phenotypes among these patients has led to the establishment of a at least one distinct syndrome: HPE, ectrodactyly, and bilateral cleft lip-palate syndrome (OMIM 300571). There has been great interest in identifying a genetic cause for the findings in patients with HPE and ectrodactyly; however the cause(s) of this rare association still remain unknown.

Holoprosencephaly, ectrodactyly, and bilateral cleft of lip and palate: exclusion of SHH, TGIF, SIX3, GLI2, TP73L, and DHCR7 as candidate genes

We describe a Brazilian boy with semilobar holoprosencephaly, ectrodactyly, bilateral cleft of lip and palate, and severe mental retardation. The karyotype was normal and the screening for mutations in the genes SHH, TGIF, SIX3, GLI2, TP73L, and DHCR7 did not show any change. This rare condition was described previously in seven male patients. Clinical and genetic aspects are discussed.

Holoprosencephaly, bilateral cleft lip and palate and ectrodactyly: another case and follow up

We describe a male patient with lobar holoprosencephaly, ectrodactyly, and cleft lip/palate, a syndrome which has been seen previously in only six patients. In addition, our patient developed hypernatraemia, which has been described in three patients before.