Idiopathic achalasia

Achalasia is a disorder of the esophagus, the tube that carries food from the mouth to the stomach. It is characterized by enlargement of the esophagus, impaired ability of the esophagus to push food down toward the stomach (peristalsis), and failure of the ring-shaped muscle at the bottom of the esophagus (the lower esophageal sphincter) to relax.^[1] Achalasia is typically diagnosed in individuals between 25 and 60 years of age. The exact etiology is unknown, however, symptoms are caused by damage to the nerves of the esophagus.^[2] Familial studies have shown evidence of a potential genetic influence. When a genetic influence is suspected, achalasia is called familial esophageal achalasia. Treatment is aimed at reducing the pressure at the lower esophageal sphincter and may include Botox, medications, or surgery.^[3]

The lower esophageal sphincter, the ring-shaped muscle at the bottom of the esophagus, normally relaxes during swallowing. In people with achalasia, this muscle ring does not relax as well.^[4] The reason for this problem is damage to the nerves of the esophagus.^[4][5] In some people, this problem appears to be inherited.^[4] There is additionally a suspected autoimmune component involved in the development of achalasia as individuals with achalasia are more likely to have a concomitant autoimmune disease than the general population.^[3] 

Most people with achalasia experience difficulty swallowing, also known as dysphagia and heartburn. Other symptoms might include: regurgitation or vomiting, noncardiac chest pain, odynophagia (painful swallowing), and pain in the upper central region of the abdomen. Non esophageal symptoms might include: coughing or asthma, chronic aspiration (breathing a foreign object such as food into the airway), hoarseness or sore throat, and unintentional weight loss.^[3]

Achalasia is suspected in individuals with dysphagia (difficulty swallowing) and in instances where regurgitation symptoms are not responsive to protein pump inhibitor medication. 

The diagnosis of achalasia is confirmed by manometry (test that measures how well the esophagus is working); however, other tests such as upper endoscopy and upper GI X-ray can additionally be useful.^[4][2]

The majority of cases of achalasia are sporadic, meaning an isolated case within a family. However there are reports of familial achalasia in which several members of the same family are affected. Familial achalasia is thought to represent less that 1% of individuals with achalasia. Although causative genes have not yet been identified, family studies have lead researchers to suspect that familial achalasia is inherited in an autosomal recessive fashion. This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell. Affected people inherit one mutated copy of the gene from each parent, who is referred to as a carrier. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When 2 carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) chance to be affected. 

Achalasia is additionally associated with several genetic disorders including triple A syndrome, familial dysautonomia, familial glucocorticoid insufficiency, and Pierre-Robin sequence.^[6][7]

Given your husband's family history, it might be helpful for your daughter to have a consultation with a gastroenterologist. The Gastroparesis and Dysmotilities Association, a non-profit organization that supports achalasia, provides information on how to find a doctor. This information can be accessed using the following link. 
http://www.digestivedistress.com/find-a-doctor

Individuals with achalasia are at an increased risk to develop cancer of the esophagus. Typically, the cancer is squamous cell type; however, an increased risk for adenocarcinoma has additionally been found. Endoscopic surveillance to screen for esophageal cancer in individuals with achalasia is controversial and often not recommended. There is limited long-term data on the incidence of esophageal cancer after surgical treatment; however, studies suggest that there might still be an increased risk.

Esophageal cancer can additionally be a cause of secondary achalasia in which individuals have symptoms of achalasia due to a primary underlying disorder.^[2]

Although there is no cure for achalasia, treatment options are estimated to be effective in 90% of cases. Without treatment, individuals with achalasia develop progressive dilation of the esophagus. This then leads to late or end-stage achalasia, characterized by esophageal tortuosity (twisting and turning), angulation, and severe dilation.

Approximately 10-15% of individuals who have undergone treatment will progress to late or end-stage achalasia. Treatment for late or end-stage achalasia is typically esophagectomy (surgery to remove all or part of the esophagus).^[2][6]