Hartsfield syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Hartsfield syndrome is a rare condition characterized by holoprosencephaly, which is an abnormality of brain development, and a malformation of the hands and feet called ectrodactyly.

During early development before birth, the brain normally divides into two halves, the right and left hemispheres. Holoprosencephaly occurs when the brain fails to divide properly. In the most severe forms of holoprosencephaly, the brain does not divide at all. These affected individuals have one central eye (cyclopia) and a tubular nasal structure (proboscis) located above the eye. Most babies with severe holoprosencephaly die before birth or soon after. In less severe cases of holoprosencephaly, the brain is partially divided. The life expectancy of these affected individuals depends on the severity of signs and symptoms.

People with Hartsfield syndrome often have other brain abnormalities associated with holoprosencephaly. Affected individuals may have a malfunctioning pituitary, which is a gland located at the base of the brain that produces several hormones. Because pituitary dysfunction leads to the partial or complete absence of these hormones, it can cause a variety of disorders. These include diabetes insipidus, which disrupts the balance between fluid intake and urine excretion; a shortage (deficiency) of growth hormone, leading to slow or delayed growth; and hypogonadotropic hypogonadism, which affects the production of hormones that direct sexual development. Dysfunction in other parts of the brain can cause seizures, feeding difficulties, and problems regulating body temperature and sleep patterns. People with Hartsfield syndrome have delayed development that ranges from mild to severe.

The other hallmark feature of Hartsfield syndrome is ectrodactyly. Ectrodactyly is a deep split in the hands, feet, or both, with missing fingers or toes and partial fusion of the remaining digits. It can affect the hands and feet on one or both sides. Other features that have been described in people with Hartsfield syndrome include premature fusion of certain bones of the skull (craniosynostosis), heart defects, abnormalities of the bones of the spine (vertebrae), and abnormal genitalia. Some affected individuals have distinctive facial features, including eyes that are widely spaced (hypertelorism) or closely spaced (hypotelorism), ears that are abnormally small or unusually shaped, and a split in the lip (cleft lip) with or without an opening in the roof of the mouth (cleft palate).

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Hartsfield syndrome is caused by mutations in the FGFR1 gene, which provides instructions for making a protein called fibroblast growth factor receptor 1 (FGFR1). This receptor interacts with proteins called fibroblast growth factors (FGFs) to trigger signaling within cells. Signaling via the FGFR1 protein is involved in many critical processes, such as cell division and the regulation of cell growth and maturation. This signaling is important for the normal development and growth of several parts of the body, including the brain, bones of the head and face (craniofacial bones), and bones in the hands and feet.

The FGFR1 gene mutations that cause Hartsfield syndrome severely disrupt the function of the FGFR1 protein, including its ability to bind to FGFs. As a result, the receptor is unable to transmit signals properly, which impairs many aspects of normal development. It is unclear how these changes lead specifically to holoprosencephaly, ectrodactyly, and the other features of Hartsfield syndrome.

Some people with Hartsfield syndrome do not have an identified mutation in the FGFR1 gene. In these cases, the cause of the condition is unknown. Researchers are looking for other genetic changes that may also be associated with this disorder.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Hartsfield syndrome can have either an autosomal dominant or autosomal recessive pattern of inheritance. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder. In these cases, the condition usually results from a new (de novo) mutation in the FGFR1 gene that occurs during the formation of reproductive cells (eggs or sperm) or in early embryonic development. Most of these affected individuals have no history of the disorder in their family. However, in a small number of cases, people with Hartsfield syndrome have inherited the altered gene from an unaffected parent who has an FGFR1 gene mutation only in the sperm or egg cells. This phenomenon is called germline mosaicism.

Less commonly, Hartsfield syndrome is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Hartsfield syndrome appears to be a rare disorder. Fewer than 20 cases have been reported in the medical literature. For unknown reasons, most of the people who have been diagnosed with this disorder are male.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Aplasia/Hypoplasia of the corpus callosum · Very frequent (99-80%)

Absence or underdevelopment of the corpus callosum.

Cleft palate · Very frequent (99-80%)

Cleft palate is a developmental defect of the palate resulting from a failure of fusion of the palatine processes and manifesting as a separation of the roof of the mouth (soft and hard palate).

Craniosynostosis · Very frequent (99-80%)

Craniosynostosis refers to the premature closure of the cranial sutures. Primary craniosynostosis refers to the closure of one or more sutures due to abnormalities in skull development, and secondary craniosynostosis results from failure of brain growth.

Depressed nasal bridge · Very frequent (99-80%)

Posterior positioning of the nasal root in relation to the overall facial profile for age.

Downslanted palpebral fissures · Very frequent (99-80%)

The palpebral fissure inclination is more than two standard deviations below the mean.

Encephalocele · Very frequent (99-80%)

A neural tube defect characterized by sac-like protrusions of the brain and the membranes that cover it through openings in the skull.

Hypertelorism · Very frequent (99-80%)

Interpupillary distance more than 2 SD above the mean (alternatively, the appearance of an increased interpupillary distance or widely spaced eyes).

Intrauterine growth retardation · Very frequent (99-80%)

An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age.

Other findings in the same source

From: Orphanet

Additional reported features include Lobar holoprosencephaly (Very frequent (99-80%)); Microphthalmia (Very frequent (99-80%)); Non-midline cleft of the upper lip (Very frequent (99-80%)); Posteriorly rotated ears (Very frequent (99-80%)); Ptosis (Very frequent (99-80%)); Telecanthus (Very frequent (99-80%)); Respiratory insufficiency (Very frequent (99-80%)); Aplasia/Hypoplasia of the radius (Frequent (79-30%)); Split hand (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Hartsfield syndrome is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Hartsfield syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.